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Charles S. Rhyne
June 1999. This article was published in Visual Resources, An International Journal of Documentation, Vol. XIL (1996), pp. 19-51. A shortened version of the article, under the same title, was published as a separate report by the Commission on Preservation and Access, Washington, DC.
Many of the web sites linked in this article have been updated since this article was published.
This article may be freely used for non-profit educational purposes. All other uses must have the written permission of the author and publisher.
In the conclusion to a recent article on digital images, world expert Michael Ester writes: "No one is asking about, let alone implementing, models of use that are sympathetic with the way professionals work."(1) Without making such an exclusive claim, this article explores such uses for research, teaching, and publication in art history and related disciplines.(2)
The Need for Scholars to Participate
The future of digital imagery has emerged as one of the central concerns of professionals in many fields. International conferences have been held and international commissions organized to examine the role of computer images and to establish standards for their use.(3) Yet these discussions are being carried on predominantly by specialists in computer technology, visual and media resources, and information management. Relatively few scholars of us have informed ourselves sufficiently to contribute to the discussion. I believe that the computer revolution is indeed to be compared to the invention of movable-type printing and the invention of photography, and that it is having a comparable, though more rapid, transforming effect on society and culture. However, the direction of this transformation and its benefits for research, teaching, and dissemination are not to be taken for granted. The potential is immense. Its realization depends on the participation of scholar-teachers in each discipline with experience in the use of images and the will to explore this new means of realizing, manipulating and sharing them. This article is, if anything, an appeal for scholar-teachers in all disciplines to speak up.
Certainly only a handful of art historians have taken advantage of the profession's unique expertise in the reading and interpretation of images.(4) As a profession, we have a great deal to contribute and a great deal to lose if we remain outside the debate. We cannot assume that the central role visual images play in our work will be fully understood by others or that the characteristics of visual images that matter most in the study of art will be valued by others. We cannot be sure that others will recognize so fully the importance of studying images through a process of free exploration, coming back from time to time to reexplore the same image differently. Others may not understand our need for examining hundreds of tiny details and of relating these to the overall experience of an object. Nor can we assume that others will have worked as fluidly as art historians with the relationships among images, formulating ideas as we browse large numbers of photographs, slides, and reproductions in books, always open to discoveries from unexpected juxtapositions.
Art historians have a critical role to play. Among the diverse disciplines at American colleges and universities, art history is by far the heaviest user of images. (Confusingly, some technical specialists have begun using the term "image" to refer to anything that appears on the computer screen, even if it is all text.) In conducting research, art historians browse photographs, slides, reproductions in books, and other images as avidly as statisticians study numbers or literary critics read text. The number of 35mm slides checked out and refiled every day in a major university slide library is astonishing to anyone who has not witnessed such an operation.(5) More importantly, art history presses the demand for image quality more insistently than any other discipline. For the great majority of art historians, who consider the visual experience of the work of art an essential part of its study, no image can fully satisfy. We always wish that we, our students, and our readers were looking instead at the work of art itself. Therefore, no matter how excellent the computer image, we always wish the color were more accurate and the resolution more detailed; not to mention that the size, texture, and opacity of art can rarely be approximated in a computer image.
In contrast, artists most intensively press the demand for free manipulation and innovative use of computer images. They are eager to experiment with any new mode of creating images and quickly discover both the potentials and limits of any computer equipment or program.
The types of digital images needed for research, publication and teaching in art history should increasingly benefit scholars and students in other disciplines. For more than a decade, slide librarians have reported that the single most significant change in the operation of their collections has been the number of non-art faculty making regular use of slides. In recent years, other disciplines have drawn on works of art, not merely as illustrations but as subject matter for investigation. As they become more involved in the study of art, professionals in other disciplines are gradually discovering the integral nature of works of art. They are recognizing that whatever aspect of the work especially interests them can easily be misinterpreted if studied apart from other aspects of the art and its overall expressive meaning or without regard for related objects. Thus, the need for large archives of images of works of art and for the most complete, detailed and accurate images possible is increasingly recognized by scholars in many disciplines as a necessity for their research and teaching.
At the same time, other disciplines, especially the sciences, are developing their own uses for digital imagery which can sometimes be applied to study in the humanities. The overlap has been most significant in conservation laboratories, where materials scientists are often part of the professional staff, and where the detailed, systematic study of objects embraces scientific procedure.
Rapidly Changing Technology and Cost / Long-Term Scholarly Objectives
This article deals only peripherally with specific computer equipment (hardware) or specific programs for running them (software). Likewise, I pay relatively little attention to costs involved. Computer technology and costs change at a rapid pace so that recommendations dependent on current technology and cost are soon out of date. I have assumed that such things as storage capacity, speed, ease of manipulation, and cost will continue to improve, and that the equipment and programs we now use will, in a few years, seem primitive. Whether or not this is true, it is important to consider what types of digital imagery would be most useful if such constraints were reduced.
This is not to claim that these constraints are irrelevant. Far from it; the technology available and its cost significantly determine what is possible at any given time at any institution or for any independent scholar or student. There is a justifiable claim that, at present, computer use reinforces the advantage of a privileged elite. Many simply cannot afford the type of equipment that one needs for everyday use, let alone for special projects. The inequalities among persons, institutions and nations are as troubling in this area as in others.
Important as the capability and cost of available computer technology is at the time decisions must be made, these are short-term decisions about what should be seen as the means to various scholarly and educational ends. In my view they have had too controlling an effect on the direction digital image projects have taken. It seems likely that some computer equipment currently being purchased by American colleges and universities will sit underused when it is discovered that the imagined use would be impractical or educationally counterproductive, or worse yet will be pressed into service despite the educational consequences. More subversively, perhaps, projects which do have serious intellectual purpose take form too unthinkingly within the parameters of available technology. Too often we allow ourselves to be captive, even in our thinking, to technology and budgets, as if they were in the nature of things rather than evolving conditions that we might influence. Whereas new, improved computer products appear constantly and are rapidly upgraded, research and teaching goals evolve slowly, based on successful approaches currently in use. It is not a natural fit. The challenge is to be open to the dramatic new possibilities of digital imagery without being misled by unrestrained enthusiasm for the new technology. This requires above all that we have a firm grounding in our disciplines and a long-term view of what we hope to accomplish in our research, teaching and in the broader dissemination of information and ideas.
Potential Values of Computer Images
What types of digital images would be of most value for research, teaching, and dissemination in art history and related disciplines? This is the central question addressed in this article. A brief answer might be "whatever types would provide the most significant advantages over types of images currently in use," that is photographs, slides, and reproductions in books and magazines. As we shall see, there are ways in which digital images are distinctly inferior to traditional types of images; but there are also ways in which, if properly developed, digital imagery offers the potential for research, teaching and dissemination at a level currently almost unimaginable. From time to time I call attention to advantages that are distinct to certain forms of teaching or dissemination, but, for the most part, I consider the usual distinctions among research, teaching, and publication unnecessarily rigid and so treat them as a continuum, activities which flow naturally into each other, are mutually supportive, and would benefit in similar ways from the development of digital imagery.
Very few of these improved images would be of types now unfamiliar to us; but so many new images could be available, to so many more people, so accessibly, at so little cost, and with a quality and detail of reproduction allowing personal, detailed exploration and manipulation now rarely possible, that the study of art would be transformed. Images would take their rightful place as essential evidence in all of the humanities and the visual arts would become a more central aspect of our common culture.
Because the potential advantages of digital imagery are interdependent, it is somewhat artificial to discuss them individually, but it will help to identify the several ways in which computer imagery must be developed if these potential advantages are to be realized. This interdependence, the varying uses to which images are put, differing views of what is of value in the world of art, and the impossibility of predicting future developments, make it unreasonable to suggest more than the most hypothetical order of importance for the potential advantages here discussed. At most, the order below serves only to call attention to the almost inverse relationship between the types of computer images and uses receiving the most commercial and journalistic attention and those which may have the most long-term potential for contributing to our understanding of the world's art.
1. Immense Numbers of New Images
Because books and magazines are filled with images of so many different works of art, it is not generally realized that most of the world's art has never been photographed, let alone digitized. One sees images of the same paintings, drawings, sculptures, architecture, and other works of art over and over again, and the most famous of these are, of course, the works that are appearing first on commercial compact disks, usually CD-ROMs.(6) Even the largest photo archives for art history research are highly selective, largely dependent on suppliers, and unable to keep pace with the modern discovery and restoration of older art, much less the creation of new. Museum collections, the most accessible and professionally supervised repositories of art, have rarely been completely photographed and in most cases only on black-white film. Untold numbers of unphotographed objects reside in museum storage and in print and drawing rooms. Only occasional manuscripts housed in vast storehouses such as the Vatican Library have been photographed.
Within the world of architecture, only the most famous buildings have been photographed at all comprehensively; this is even more true with vernacular architecture and industrial archaeology. Likewise with sculpture, only the masterpieces of world art have been photographed from a sufficient number of angles to support detailed study, many photographs of sculpture are not in color, and less famous sculpture and tribal objects are photographed inadequately or not at all.
In class, intelligent students regularly ask questions that cannot be answered on the basis of available slides or reproductions. For students and scholars wishing to study a work of art in depth, the lack of adequate slides and reproductions in books, even of photographs in photo archives, quickly becomes apparent. Of course, for such study one must travel to see the object firsthand, but one cannot return to Berlin or Bombay every time one has a new question about a work of art. Unless one has photographed a work of art thoroughly while on site, there will almost always be major unanswered questions. Moreover, some museums deny photographic rights even to scholars, and it is not possible to take paintings off the wall, much less out of their frames, or to remove sculptures from their cases, except in rare circumstances. Being on site does not make it possible to see a building in its partially ruined condition before it was reconstructed or to erect scaffolding to examine upper sections of the present facade. In all of these ways, one is dependent on photographs, in most cases nonexistent.
Within the world of scholarship, studies of art are increasingly based on everyday images, costume and material culture, on tribal art housed in museums of natural history or ceremonial objects in use, on temporary outdoor sculpture, on famous works of art in previous conditions or as previously displayed, on all the paintings exhibited at landmark exhibitions, and on utilitarian structures, vernacular architecture, and urban districts. Most of these have not been adequately recorded.
The appearance of digital imagery has coincided with a recognition of the need for images of these disparate and previously undervalued forms of art, for adequate details of traditional art, and for images of art as it has changed and is changing physically over time. Most influentially, the digital revolution has coincided with an increased demand for public access. As a result, a number of major public museums have undertaken digital image projects aimed at photographing or rephotographing nearly their entire collections and making them available through digital imagery.(7) One cannot praise enough the dedication of those responsible for these projects. The enthusiasm for and promise of this new technology, its increasing cost efficiency and potential for broad public access offer us a fresh opportunity to further the process of adequately recording the world's art. Whenever a museum is able to undertake a digital image project of its collections, it should take advantage of the opportunity to record, as nearly as possible, every artifact in its collection in as thorough a way as possible. Government agencies should revitalize their efforts to record adequately the monuments and public art under their care, and research institutions should extend their photographic campaigns in areas of their expertise.(8)
A closely related and more obvious potential advantage of digital imagery is the wider public availability of the massive numbers of already existing images. But it may eventually be in the seemingly prosaic provision of an immense number of new, higher quality images, not entirely dependent on but stimulated by the new technology, that digital imagery makes its most significant contribution. The fact that it would be extremely costly and would require many years to provide does not alter the fact that for research, teaching and the dissemination of information and ideas, image data banks are needed that are as comprehensive, accurate, and available as data banks of texts.
2. Greater Quality / Fidelity
No potential of digital imagery is more unrecognized and undervalued than fidelity to the appearance of the original works of art, yet none carries more promise for transforming the study of art. Why is fidelity so crucial? It is a matter of historical accuracy and responsibility to evidence, at base perhaps a matter of ethics. If we claim to be recording an important object created by another human being, let the image look as nearly as possible like that object and not some aberrant version. If we wish students to experience the visual character of an object, to explore for themselves how the forms, colors, and textures interpret the subject depicted, let them experience an image of the object that is as accurate as possible. And if we wish to convey to others our understanding of these complex cultural artifacts, let those who hear and read our words have the opportunity to form their own judgments as we have, based, if not on first-hand experience of the original, at least on the most accurate possible images. The history of art is too often the history of slides and reproductions. Let us at least do what we can to make the one approximate the other.
With each jump in quality, new uses become possible. Most of the images of art available on CD-ROMs, on institutional file servers, and over the Internet are adequate only for identification. They tell us what objects are available at a given museum, which objects were included in the lectures for a class, and they provide illustrations for accompanying texts. In many situations this is the primary need and, especially where previously no images have been available, such images provide a service of immense value. These delivery mechanisms are making possible a revolution in public access to images. However, in terms of quality, most serve only as substitutes for run-of-the mill reproductions in books and are not even as informative as the photographs and slides they often replace. Even in terms of identification, one would not want to rely on these images to distinguish between a work of art and a copy of it.
With images of somewhat higher quality, color becomes more reliable and one can begin to see details with some clarity. When displayed on a large video monitor or projected, such images seem to serve adequately for discussion in grade or high school classes where student participation and ease and speed of manipulation might be valued more highly than fidelity to object.(9) Museum that have made available CD-ROMs with digital images of their collections, even when produced only at this moderate level of quality, have contributed to the public interest in art. Images of this moderate quality might be acceptable also on CD-ROMs which discuss social history or other subjects which do not encourage response to the visual qualities of art. In all of these cases, however, the unity and overall impact of a work of art is being sacrificed for a simple reading of surface information, and the opportunity for the viewer to discover an inspiring work of art is compromised. Do we not value the opportunity for students to think to themselves: "Wow, that's an amazing painting; I'd love to see that sometime"?
What has been overlooked in most discussions of digital imagery is the immense potential of high quality images. Because these are currently expensive to produce, require an amount of memory available only to well-funded projects, would overload the Internet if distributed in significant numbers, and because owners of these works of art and transparencies fear the commercial exploitation of their property (because of the current ambiguity regarding fair use and the difficulty of enforcing copyright), too few of us have even experienced high quality digital images of art; and I have read nothing that explains how research, teaching, and the dissemination of information and ideas would be transformed if high quality images were available.
Quite the contrary, moderate degrees of detail and color fidelity are being proposed as international standards and recommended by even the finest producers of CD-ROMs,(10) partly for the practical reasons mentioned above, but also because the immense potential of high quality images has yet to be recognized. Because carefully conducted studies show that, when looking at digital images on computer monitors, human beings cannot distinguish between images with high resolutions and those with moderate resolutions,(11) the conclusion is easily reached that extremely high resolutions are unnecessary, useful only for printing high-quality commercial advertisements and glossy annual reports to stockholders (the best printers have much higher resolution than monitors). This conclusion is reinforced by the fact that computer monitors currently available cannot display the full amount of detail and color fidelity recorded in extremely high quality digital images; thus an extremely high resolution digital record appears no better on the computer monitor than a record with moderate resolution.
But this is true only when looking at the full digital image. As soon as one zooms in to enlarge details, the moderate quality image pixelates, whereas the high quality image allows one to move in and examine details with clarity. With images recorded at extremely high resolution one can zoom in amazingly far to examine the construction of an arch, the way a painter has varied brush strokes to convey different surfaces and materials, and to read inscriptions and the text on medieval manuscripts.(12) The relevance of studies demonstrating the limits of human perception largely disappears once one recognizes the capacity of computer imagery to approximate the normal process by which people move back and forth between viewing the overall work of art and exploring it in detail. The limits of human perception are largely irrelevant also for machine analysis of images, so essential if we are to develop image-searching comparable to text-searching, surely one of the most useful functions of computers.
With few exceptions,(13) this tremendous capacity of digital imagery has not been taken advantage of in the production of CD-ROMs of museum collections. Image quality has been sacrificed to inventive navigation design within the CD-ROM. Most CD-ROMs produced by museums and other institutions claim to provide interactive flexibility but are in fact highly programmatic. Most current CD-ROMs are like little books, completely programmed and neatly packaged. They serve admirably the purpose of introducing the viewer to the works of art in a museum and of providing related information, but are of little use beyond that. It takes several minutes to get past the introductory material and to figure out how to navigate the system, which each CD-ROM designer seems eager to design in an improved, but incompatible format.
One proceeds down various paths, arriving at a reasonably informative text accompanied by a mediocre image that cannot be examined in any detail; then down another path to another mediocre image, and so forth. It is fun the first few times. One learns to recognize the paintings and what is represented in each and reads about how this relates to the religious ideas at the time or events in the painter's life, perhaps even how the painting had deteriorated and was then restored. One hardly notices the inadequate images as one flicks from one to another, with accompanying text available. But once interested in any image, the viewer is frustrated by the inability to see anything clearly or in detail.
If there is a central pedagogical point to be made regarding the use of digital imagery, it is that the best teaching, like the best research, requires free exploration. One does not examine art just to answer prescribed questions. One looks at art to see what is there, to explore anything that captures one's attention. We cannot foresee what we as scholars will discover or what a student will find of interest. What are the figures in the background doing? How is the woman's hair braided? What is holding up the sculpture? How is the reflection in the mirror painted? What is on top of the building? What is the expression on that person's face? What does the inscription say? To answer such questions we need very high resolution images and the ability to zoom in to examine details. Moreover, we need to be able to do this in a manner approximating as closely as possible the way in which we, quite naturally, examine works of art. We need to be able to move in smoothly, not jump from the overall image to a close up, then another. We need to be able to scroll from side to side smoothly at whatever speed we choose. If we wish to examine one of the windows on a facade in detail, then gradually compare it with those on either side, then scan quickly to see if we can spot other windows of similar design, then return to examine a damaged portion of the window that had earlier caught our eye, all this should and could be possible.
If imagery and technology of this sort were available, can we imagine with what eagerness students would examine digital images in preparation for class discussion or research projects, and how much they would discover? And can we imagine how scholarly research, teaching and publication would be transformed if, like texts, this type of visual evidence were available in our offices when we were formulating ideas and writing?
More demanding of course is the need for images of three-dimension objects, sculpture and architecture. Here, in addition to the types of exploration desirable for studying paintings and other relatively flat objects, we should like to be able to move around three dimensional objects and, for architecture, also within its spaces. As with paintings, we should like to be able to do this at our own pace (not viewing a film), following our own path and looking in whatever direction we wish. And we should like to be able to move up close to examine details of whatever catches our attention. Although still at a primitive stage of development, these types of visualization already exist and need only to be developed in ways that will allow us to explore sculpture and architecture as freely, in as much detail, and with as much fidelity to the original objects as possible. (Digital viewing of this type, often combined with sound and other sensations, goes by the now famous label "virtual reality," discussed further in section 7 on modeling and image modification.)
This article deals almost exclusively with images of works of art and other objects as they are seen in the real world. These include images photographed from drawings or prints of maps, charts, and other types of diagrams. But there are also maps, charts, diagrams, etc. that are created in the computer. Here there is no real-life object against which to test the fidelity of the image, and one judges the image rather by its fidelity to the concept one is attempting to diagram, as well as by its clarity and, often of great importance, the ease with which the diagrams can be manipulated to test complex alternatives. For example, biologists regularly use digital imagery of the real world, usually microscopic, whereas chemists almost always work with models of structures created in the computer, which can then be manipulated in complex ways. Although art historians and other humanists predominantly use images of the real world, including ground plans and elevations of architecture taken from real-life drawings or prints, we are learning to make use of the programs so heavily used by architects for creating three-dimensional drawings within the computer, which can then be manipulated (computer aided design or CAD).
In the process of producing computer images, the weakest link in the chain determines the quality of what we see. It is true that certain corrections can be made to a slide or transparency that is underexposed or in other ways misrepresents the work of art depicted. For the most part, however, any inadequacies in the conditions under which a work of art was photographed, any inadequacies in the camera lens, in the grain or color fidelity of the film, in the angle or exposure of the slide or transparency, in the development of the film, in the scanning of the image, in its manipulation within the computer, in its archival storage, in its compression for any particular use, or in its display on a computer monitor or projection on a screen will show themselves in the image we see. It is essential, therefore, if we care about the fidelity of the final image, that we attend to each step in the process.
In terms of quality, the most important part of the process remains that which precedes use of the computer, the remarkable ability of film to record detail with extraordinary precision and accuracy. (The remarkable exception of direct digital capture in conservation laboratories is discussed at the end of this section.) Even the highest resolution computer imagery based on film cannot capture this remarkable detail. Somehow this still surprises people, although it should be obvious that a copy can be no more accurate than the original against which its accuracy is being judged. It is easy enough to confirm this. Have a high quality, original 35mm slide of a detailed painting digitized at extremely high resolution by the finest professional lab. Then view this digitized image on a very high quality computer monitor, zooming in to enlarge details of a face or pattern in the floor. If we then examine these same details in the 35mm slide itself with a standard 8x lupe, we will find that we can see the details a little more precisely in the slide. Lines are a bit sharper; the distinctions between one form and another are a bit clearer; colors are a bit more distinct. Preserved on those remarkable pieces of film, the images only 35mm in length (less than 1 1/2 inches), are the most amazingly accurate, detailed records of the world's art, made possible by the miracle of photography. Moreover, we have more confidence in the reliability of the slide for recording the appearance of the work of art, because it has not gone through an additional process of duplication.
The quality of the original slide or transparency depends to a great extent on the ability of the photographer. Likewise, the scanning of the slide into a digitized format is not simply a mechanical operation but depends, though hardly to the same extent, on the skill and understanding of the person carrying out the process, and even a perfectly digitized image can be distorted through inept manipulation. In everything to do with computers, there is a naive trust in technology. For example, it is regularly said that, unlike duplicating a slide or transparency, copying a digital record produces an exact replica, even to the tenth or hundredth generation. Conceptually, this may be true, but even this is vulnerable to deterioration of material, machine malfunction, or human error.
Because there are so many steps involved in the production of a digital image, and because the ways in which it has been affected by each step will not be visible in the final image, it is essential, if we care about the fidelity of the final product, that the process used in each step be recorded and available to users of the image. Admittedly, this information has rarely been provided even with photographs, slides and transparencies, which are only the starting point for digital images. The standard first lesson for students beginning the serious study of photography is that photographs lie. No doubt this is a useful warning, but is it not rather the case that every photograph tells the truth? That is, each photograph records exactly the way a given object or scene looked under those lighting conditions, using that camera with that lens and that film, at that exposure, developed and printed in that way. The warning that all photographs lie leaves us to enjoy an invented, relativistic image; whereas the claim that all photographs tell the truth leads us to enquire about the conditions under which the photograph was produced, in order that we can better know what we are seeing. Perhaps the well publicized editing and image modifications possible with digital imagery will finally encourage us to record these, at least for images to be used in research.
I have been using the terms "quality" and "fidelity" almost interchangeably. But of course what one means by "quality" varies according to what one values in an image. If one is attempting to sell posters illustrating a work of art, quality may lie in the image's beauty or commercial appeal. But when one is conducting historical research or discussing a work of art in class, we would always prefer to be looking at the work of art itself (assuming one is really studying the art rather than something else). Hence, as historical documents, images of art are valued to the extent that they approximate what one would see if looking at the work of art.(14)
Such a standard is exceedingly complex. Not only can the image never match the appearance of the original work of art, but there are a variety of ways in which this is true, and in each of these ways there will be different degrees in which an image will approximate the appearance of the object it depicts. Moreover, what constitutes the appearance of the original is variable, and human perception is not a static process. It is clear that there are immense differences between our viewing of an original work of art and our viewing of its digital image on a computer monitor. Nevertheless, while recognizing these differences, fidelity to the appearance of the original work of art remains the overall standard we attempt to approximate, and taking these photographs under selective or controlled conditions which we record can help us more nearly to achieve this and to recognize the waysin which we do not.
Because cameras commercially available for direct digital capture are designed for speed and ease of use and therefore produce very low resolution images, it is easy to suppose that direct capture is inherently inferior to images digitized from high quality transparencies. Especially where one begins with a 4 x 5 inch, or even better an 8 x 10 inch original color transparency which is then digitized by a top quality professional lab at very high resolution, the digital image can be remarkably true to the work of art it represents. But zooming in to examine details, one eventually discovers that the brushstrokes with which an eye is painted or the knife marks with which a nose is carved are less clear than if one is looking at the work of art itself. Amazingly, in the very highest quality direct digital capture in conservation laboratories, one can see these brush strokes and knife marks not only as sharply as in the original object but as if looking through a magnifying glass. This process is normally used for technical studies, not the normal viewing of works of art, and so is discussed only briefly here. It requires complex, extremely expensive, custom designed equipment, available in only a few conservation laboratories in the world - and on space shuttles.
But we should note that digital images of works of art with spectacular accuracy and detail are already possible. Methods of direct capture have been developed in three conservation laboratories, each emphasizing a different aspect of fidelity. One approach emphasizes the recording of surface characteristics in such detail that one can compare two different digital images of a hairline crack in a paint surface to see if it has widened even minutely.(15) A second emphasizes the recording of color so carefully calibrated that one can detect infinitesimal color change over time.(16) The third emphasizes recording of three-dimensionality so that even slight changes in three-dimensionality are noted.(17) Although these procedures have been developed for technical study beyond the range of normal human vision and therefore have highly specialized uses, it is not unreasonable to hope for vastly improved digital imagery for normal viewing that has profited from these laboratory developments. A reasonable standard to which we should aspire for digital images of works of art is one that would allow us to zoom in on the computer screen to see details of works of art at life size with as nearly as possible the same amount of detail visible as one could see if viewing the original object under museum conditions.
3. Availability to More People
The possibility of making images of works of art available to many people who previously have not had access to these images in any form is, from a social point of view, the most significant potential advantage of digital imagery. Since most people without access to images in books also do not have access to computers, we are not speaking yet of rural and third world peoples, though computer access in these areas may not be in the distant future. The current promise of wider availability consists of making publicly available such images as illustrations in publications housed in specialized libraries, research slides taken and collected by scholars in many fields,(18) and especially the vast stocks of unpublished photographs currently available only to those with access to photo archives in museums, universities, cultural research institutes, conservation laboratories, organizations such as the National Geographic Society, and governmental agencies of all types both at the national and local level.
Many of these images could be made available on CD-ROMs, which have established a secure position in the marketplace. CD-ROMs featuring images of art are now on sale in the racks of local computer stores and advertised in glossy mail-order catalogues, even on the back of Time magazine. Museums are publishing CD-ROMs in conjunction with their major exhibitions and selling them in their bookstores. However, digitized images that have been made available commercially on CD-ROMs have been largely well-known images already available in books and as slides. Most CD-ROMs recycle the standard images in a new format, usually with lower quality, in many cases simply taking advantage of the current fascination with computer manipulation. It is doubtful that CD-ROMs of art have yet reached an audience without ready access to most of the same images in books. In some cases, familiar images have been incorporated in guided tours of museums, exhibitions, and cultural heritage sites, with the mandatory interactive options, in this format no doubt reaching many who do have access to the same images in books and catalogues but do not make use of them.
Photo CDs (a type of CD-ROM) have been adopted by many individuals and institutions as their standard medium for digitizing and archiving images. To have access to an image on a Photo CD or CD-ROM, one must of course have the CD or access to it in the first place. Only a limited number of images can be recorded on any one CD, and calling up high resolution images from CDs is a relatively slow process, currently too frustrating for most people wishing to view a large number of images.
Moreover, CD-ROMs are like closed books, with a variety of formats, many unique, including enforced introductory material, with images that can only be used when the CD-ROM is physically present in the computer's CD-ROM slot. Except in cases where a large concentration of high quality images on a single, limited subject are made available on a single disk or group of disks,(19) CD-ROMs provide no educational advantage over traditional materials.
The best education, like the best research, requires flexibility and free exploration. Images on most CD-ROMs and Photo CDs become educationally useful when they are copied onto institutional file servers, where thousands of images can be accessed by many different viewers at the same time, in the convenience of their offices and dormitory rooms, calling up images in any order or combination they wish with a few clicks of the mouse. Although facilitated by CDs, it is this step of putting digitized images on file servers that is making images of art available to large numbers of people without previous access. In order to accomplish this, a few museums and slide companies have made available digitized images previously available only as high quality slides.(20) Most of these projects at colleges and universities consist of low-moderate resolution images of slides related to specific classes (art history, studio art, architecture, historic preservation, etc.). For students to be able to view instead the types of high quality images needed for the study of art, it will be important to have major increases in storage capacity and speed of access and servers dedicated to classes that require such images.(21)
To date, these projects have been initiated almost always by slide librarians and computer information specialists and have been funded outside of academic department budgets. As far as I can tell, they are always low resolution images used almost exclusively for voluntary student review. There must be others, but to date I have found only one department in which art historians have actually assigned high quality computer images for study in standard art history courses, that is in courses in which computer imagery was not one of the subjects under study.(22) This number is certain to increase significantly during the 1995-96 academic year. Quality determines use. In a few cases, massive archives of digital images are being put on institutional file servers for use in a wide variety of disciplines.(23) Especially at large universities, these have the considerable benefit of making available images, albeit usually of low-moderate quality, to many thousands of students who do not have use of the visual resource collections on campus. For the immediate future, institutional servers seem likely to remain the preferred medium of availability for image archives. A promising alternative are regional servers, which have the potential of serving much larger communities, with all the attendant benefits of cooperation and increased resources, while avoiding duplication of effort and expense. For these to carry images in sufficient numbers and with reasonably high resolution, we may require that cables (usually fiber optic) be installed with substantial bandwidth, connecting the regional institutions. Existing telecommunications links can sometimes be used.(24)
Even more people have access to the Internet, and the number is growing at an astonishing rate. Under present conditions, in which, with few exceptions,(25) only low resolution images are available on the Internet, the quality of these images cannot compete with even average CD images, much less with the few CDs of outstanding quality. Without regard to quality, however, images on the internet are beginning to provide information worldwide, not dependent on verbal language distinctions that make the present internet largely an English speaking form of communication. Most importantly, these images can appear with the speed of daily newspapers, making available multiple color images of newly discovered or newly created objects overnight.(26) For now, the rapidly increasing overload of the internet and its potential for gridlock if even moderate to high resolution color images were loaded on the internet in any numbers, makes extensive exchange unlikely for images that are useful for anything beyond generalized recognition. Universal human access to images comparable in quality even to those that appear in weekly news magazines will probably have to await the development of some form of airwave or satellite system, which can handle vastly larger amounts of digital information, so necessary for reasonably high quality color images, and which can transmit them without dependence on copper wires or fiber optic cables.(27)
Those of us in art history and related disciplines, who recognize the need for image standards far above those acceptable in other fields, need to involve ourselves in the resolution of two key issues: the development of international standards for the capture, storage, transmission and description of images; and the resolution of the complex issues of copyright and fair use. Until we can reach agreement not only on the conditions under which copies can legally be made, but even on what constitutes a copy, the types of high quality digital images of art necessary for research, teaching and dissemination are unlikely to be available outside of a privileged elite. These two key issues are too complex to be examined here but they underlie all future development of digital imaging for art history and related disciplines.(28)
4. Easier and Faster Access
In comparing the ease and speed of access to digital images with access to slides or illustrations in books, it is important to think in practical terms about the various uses to which images of art are put in a typical class. Images of all kinds are browsed in large numbers by faculty and teaching assistants in preparation for classes. Images selected are then studied in detail. Some, usually illustrations in books, are assigned for student study in preparation for class. During lectures, student reports and class discussion, images are usually projected, but occasionally viewed on video or computer monitors, and in small seminars sometimes in books. Images are reviewed after classes and in preparation for exams. During research for class reports and papers, students browse images in large numbers, studying key images in detail and reproducing those discussed in their research papers.
These images are drawn from a number of sources. Students have typically been limited largely to reproductions in books and magazines or to photographs posted for specific classes. At some institutions, lecture slides are made available for review and identification after each class. When preparing class reports, students often have some access to institutional slide collections. Faculty and teaching assistants typically make heavy use of institutional slide collections and, where they are available, of photographic archives. Some faculty draw heavily on their personal slide collections.
For which of these uses might digital images provide easier or faster access? For browsing large numbers of slides in preparation for class, it seems clear that being able to call up images on a computer screen could be immensely faster and, especially in one's office, immensely more convenient than pulling slides from cabinets in the slide room. However, until all the usable slides in the slide collection are digitized, one would run the risk of missing key images, and even if the images were put on at relatively high resolution one would not be able to study the slides in as much detail as with an 8x lupe, though surely with less eye strain. Moreover, in spite of the much heralded ability to tile many images on a computer screen, if one were examining a sizable number of images, these would become crowded more quickly than on a slide room light table. Under ideal conditions, however, with images of all usable slides available at extremely high resolution and with near-immediate computer response, the ease of accessing the images, enlarging them and zooming in to examine details would far outweigh the current advantages of the traditional slide room. One must add, however, that until reliable and high quality computer projection is available in classrooms, the slides would still have to be pulled and some of those chosen might be checked out or missing.
The potential advantages of assigning computer images instead of reproductions in books for class preparation depends on the availability of specific images and their comparative quality. For class preparation, one needs images of specific works of art and images that record specific types of information about them, and because these are to be studied with some care, one needs the highest quality available. For smaller classes, one would presumably assign whichever images best serve the purposes of the assignment, drawing both on computer and printed images. In large classes, where expensive art books cannot be assigned for study, computer images offer, for the first time, the possibility of assigning high quality color images for student study. This one use of digital imagery could transform the study of art in large introductory classes. It is hard to imagine a more immediate benefit to the study of art history at undergraduate institutions than the acquisition of very high quality digital images of the art studied in large introductory classes, loading them onto institutional servers, and making the images available to students on large, high quality monitors.
The projection of digital images of art for lectures currently offers no educational advantage over slide projection. The technology for projecting digital images with acceptable quality for art history lectures is available only at extreme cost and with a technician available to tune the projector at frequent intervals. Even then, the possibility that projector malfunction might scuttle an entire lecture is enough of a threat to discourage any lecturer, not forced by administrative decree, from giving up the relatively secure, field-tested, use of slide projectors. Eventually, digital projection will be equally reliable and, at that point, will eliminate the time consuming job of pulling and refiling slides.
Discussion classes and seminars are another matter. There are innumerable times when a different work of art, sometimes from a previous meeting of the class, or a different view of the work under discussion would provide exactly the evidence necessary for a question asked or the point under debate. Even where the slide room and classroom are adjoining, the time necessary to locate and pull the crucial slide would cause too severe a break in the discussion so one does without. If the projector were linked to the slide room server, one could project such images almost at a moment's notice. For this reason, if not for lectures, digital projectors will eventually facilitate the serious study of art.
For class review and exam preparation, the convenience of viewing a large number of images with accompanying identifications instead of turning through a shelf of books offers obvious advantages, not to mention the ease of reviewing in one's dorm room or apartment. For text, paperbacks offer the advantage of reading in the bus or under a tree, but high quality reproductions appear in large, expensive books, and must normally be studied in the library. Digitizing the majority of slides in a typical university slide library is such an extended project that current technology will almost certainly be superseded before such projects can be finished. On the other hand, digitizing the images necessary for individual courses is manageable and has immediate use for student review.
For research, and to a lesser extent for class preparation and other study, reproductions in books offer the fundamental advantage of context. Each image of a work of art is surrounded by images of other related works, by diagrams, descriptive text, historical narrative or theoretical argument, and by a bibliography and index. Short of putting all of this on the computer, the importance of digital images for research depends on the availability of images that are different or of higher quality than those in books and slides, on the speed with which images can be put on the internet in contrast to the slow pace of publication, and, for some research, on the ease with which computer images can be manipulated.
5. Less / More Expensive
One of the common misconceptions about digital imagery is that it will provide significant savings for institutions now funding slide collections. The first point to be made is that digital images will not completely replace slide collections for many years, if ever. Therefore, although there will eventually be saving when hundreds of new images can be stored on CDs in the space previously required for a few slides and when fewer and fewer slides need to be refiled; digital imagery will primarily be a new, additional body of material, however compact. Likewise, when digital projectors have been developed to the point that they are usable in art history classrooms, they will be added to slide projection systems, not replace them. Moreover, the danger of large scale destruction of digital storage argues against any institution getting rid of its slide collection.
We are all aware that any computer project requires considerable initial expense for equipment, software and supplies, the training of personnel, and for scanning in-house or outside. What is only gradually becoming recognized is the necessity for continual upgrading. Some of these expenses will involve only slight retraining of personnel or purchase of more up-to-date equipment; but it will occasionally be necessary to recopy all digital files or to transpose all of them to a new format. And when reasonably priced, higher resolution scanners become available, will institutions rescan? It is not at all unreasonable to expect that new technological developments will make available, from time to time, types of imaging not yet imagined, with such advantages (among them probably the claim of significant savings) that institutions will want to add yet another form of imagery.
The prospect of digitizing slide collections has encouraged some institutions to restudy, make consistent, and sometimes redesign their indexing and labeling procedures, and to make or purchase new, higher quality slides. This is all to the good, but it does not save money.
Saving will come only when a system is in place for directing buyers to available sources for any image, with designations for differences in quality, price, and use, and for providing accurate, detailed catalogue and label information. It boggles the mind that institutions all over the world continue, individually, to photograph their own slides from the same illustrations in the same books, and individually to catalogue and label them.
The other area in which digital imagery might make significant savings possible is in the field of publishing. Journals, for example, if published electronically could provide savings in any subject but especially for those requiring high quality illustrations. In general, however, it is difficult to see how digital imagery can produce savings in the foreseeable future.
6. More Permanent
We have gradually come to realize that the much publicized claim that information stored in digital electronic form is permanent needs major qualification. The digital concept is indeed permanent, based as it is on the absolutely clear and invariable distinction between zero and one. However, all information created by human beings can be saved only in the minds of living humans or as part of some material object, and both of these are subject to change and destruction.
Nevertheless, digital records do have a number of characteristics which, in some ways at least, make them more useful for the permanent recording of images than any previous means. One of these is the remarkable fact that, unlike all previous means of preserving images, digital records do not gradually deteriorate. Even reading a CD-ROM many times does not shorten its life, because the laser used in a CD-ROM drive is very low power and does not harm the disk. If the digital record survives, it remains exactly as originally recorded. This means that, for the first time in human history, we can make reasonably accurate comparisons between the appearance of works of art at different times. This is most unprecedented in the recording of color. Because color fades in all objects (amazingly fast in watercolors, amazingly slowly in glazed ceramics) and in all photographs and transparencies, all previous comparisons have depended on images that had faded in different degrees. With digital imagery, this is no longer the case.
Equally remarkable is the fact that digital records can be copied over and over again without the gradual image deterioration characteristic of photographic copies. If there is no flaw in the process, the hundredth digital copy is identical to the original. Even here, of course, one must remember that all technology involves equipment, procedures, and human involvement, any one of which can be flawed. Experience teaches us that mistakes will be made.
Like very high quality color transparencies, high quality digital imagery offers the possibility of making images of works of art available for some uses in cases where the original works of art are themselves highly impermanent or, as in the case of medieval manuscripts where the pages must be turned, are easily damaged by use.
There is the additional virtue that images can be projected digitally for long periods without damaging the digital record. Although teachers seldom pay attention to this unless it is their own research slides, projection causes fading of color slides, in the case of some color film distressingly quickly.(29) For those who take pride in projecting high quality, original color slides, especially when class discussion turns on the visual appearance of the art, the prospect of being able to leave a high quality image on the screen for ten or fifteen minutes while the artist's account of the work or a later critic's comments are being debated is inviting in the extreme.
Set against these remarkable characteristics are the realities of the material world and human behavior. There are different types of CDs, some produced by several different manufacturers. They vary in the materials out of which they are made, in their methods of construction, and in the quality of both materials and process. Estimates vary widely concerning their usable life spans. In contrast to photographs, slides, and color transparencies, which one can observe gradually fading and thereby decide whether or not to copy and at what point, digital records completely stop working without notice. Moreover, digital images can be viewed only if the necessary equipment and computer programs are available. Unlike slides and transparencies, they cannot be held up to the light and viewed, however imperfectly.
Moreover, CDs are easily damaged. Inside the jewelbox of Kodak Photo CD's are nine little diagrams indicating that the Photo CD should be (1) held by its edges, (2) kept at temperatures below 40° C/104° F, and that one should not (3) put on labels, (4) write on the CD, (5) leave it in the sunlight, (6) apply liquids, (7) expose it to dust, (8) scratch the surface, or (9) touch the surface with fingers. Instructions in jewelboxes of various CD-ROM producers add instructions about not storing the CD near heat, not bending it, not placing it face down on a hard surface, cleaning only with a soft, dry cloth, and not using gasoline, kerosene, benzene, lacquer thinner, anti-static agents, or LP record cleaners.
Of more concern than the im/permanence of the physical objects on which digital images are recorded is the im/permanence of the formats in which they are recorded and the systems for reading them. Given the relative infancy of the digital language, the inexorable march of technology, and the now obvious rewards for anyone who invents a dramatically improved format or system, it seems clear that new digital formats will replace those now in use and new systems be developed.(30) It may even be that some as-yet unimagined form of image recording will replace the digital language. It is unlikely that many institutions will preserve not only their earlier digital records but also the accompanying computer equipment, operating systems, software, spare parts, and instruction manuals. Therefore, at the very least, digital records will need to be recopied at regular intervals and transposed into new formats as they become available. At each stage there is the possibility that some types of information will be altered or lost. Therefore, it is important that all digital image records be stored in multiple forms, especially in ones that seem likely to allow for transposition to new formats and new systems.(31)
7. Modeling and Image Modification
Based on the amount of attention given to them in newspapers and magazines, even in papers at professional meetings, one might guess that the most important uses of digital imagery are those made possible by the fascinating new types of computer modeling and various forms of image modification. A few of these have indeed established themselves as major new tools for research, teaching, and publication in art history and related disciplines; while others have important specialized uses in fields such as art conservation. But none can be said to equal in potential importance the day-by-day value of immense numbers of new, high quality images and their availability to large numbers of people. In fact, the most promising of these new approaches are important partly because they would make available large numbers of new images.
The most astonishing of these new approaches are modeling programs that give us the ability, visually, to walk around sculpture, looking at it from whatever angle and from whatever distance we wish, and to walk through architectural spaces, even viewing facades and interiors as if from scaffolding or floating in space. This gives us previously undreamed of potential for the study of 3-dimensional artifacts and buildings. These 3-D visualizations depend on the provision of immense numbers of new slides and transparencies taken under controlled conditions with prescribed lenses specifically for this purpose, and partly on new computer programs which allow us to combine these images to simulate a fluid, self-directed process of looking.(32) Just as the availability of new, high quality images of 2-dimensional objects could transform the study of paintings, drawings, prints, and textiles, etc.; so the vastly more demanding provision of new, high quality images of the 3-dimensional arts, integrated to simulate real forms and real spaces explored in real time, could transform the study of sculpture, artifacts, and architecture. Known by the now famous label "virtual reality," such images can be joined with sounds and other sensory perceptions to simulate a fuller experience of the art being studied.
In addition to these constructions of 3-dimensional forms and spaces from photographic images of art and architecture, 3-dimensional models of sculpture and architecture can be created entirely in the computer. Typically, these use programs for computer aided design (CAD), which have been the mainstay of architectural offices for several years and have been available in less developed forms for well over a decade. These programs allow us to create in the computer a line drawing of a sculpture or building, in correct perspective, which we can then turn and view from any angle, any distance, from outside or inside the transparent wire frame of the drawing. The primary use of such drawings is the design of new sculpture and new architecture, allowing designers to consider their ideas from hundreds of angles and distances without the difficulty and labor of producing hundreds of different perspective drawings. CAD has also been used extensively by architectural restorers, starting with measured perspective drawings of already existent buildings, which they then redraw in various ways to consider alternative restorations.(33)
Art historians have adopted these remarkable modes of 3-dimensional modeling. Using CAD, art historians have created transparent perspective drawings of buildings that have been destroyed or damaged, as the basis for historical reconstruction. Where portions of these buildings or their decorative/pictorial schemes still exist, these have been superimposed on the wireframe drawings and the remaining portions of the building often drawn or painted in hypothetically.
These combination drawing-photographs allow one to walk through a building or architectural site, studying its form, furnishing, sculpture, wall paintings, mosaics, anything that one has added to the image, from an endless succession of angles, moving closer or farther away and at whatever pace one wishes. This exactly parallels the virtual reality of existent buildings constructed of recent photographs. To the extent that these collages are hypothetical, they are less direct as an access to understanding real works of art. On the other hand, they stimulate more extensive experimentation and imaginative thinking. For this, an essential feature is the automatic linking of any change made in one view of a drawing with other, previously unpredicted but consistent, changes in other views of the drawing. In both types of reconstruction, there are important discoveries to be made regarding such things as relationships among images, perspective adjustments made by artists, and the ways in which processional routes or the location of relics and monuments influenced architectural design.
As a research tool, such studies have produced new understandings of famous monuments, thoroughly studied in the past but without benefit of computer technology.(34) More commonly, such reconstructions have been used to demonstrate discoveries already made and to allow the public to navigate their own way through digital reconstructions of architectural spaces, such as Egyptian tombs or Roman cities.(35) Although these demonstrations are now increasingly interactive, the viewer is limited to movements and views programmed in by the creators of the demonstration; whereas research uses, including student projects, allow one to create and explore freely, using any function of which the computer is capable. At present, computer aided design deals most successfully with geometric forms. For sculpture and other artifacts, it is important to develop CAD's ability to image irregular object with complex curving surfaces.
In addition to these more dramatic 3-dimension visualizations, several types of 2-dimensional image modification are producing impressive results. In all of these, there is the danger that the appearance of the original work of art will be distorted in order to make the computer image more "attractive," to remove reflections or blemishes, to increase the intensity of certain colors, or to straighten uneven edges; but where these modifications are specified and have specific purposes, they can provide useful study tools. In some cases, these are simple changes of dark-light contrast to make images more readable. In other cases, art historians have overlayed genuine signatures or stamps with questionable examples as an aid in judging their authenticity. In others, they are overlaying sequences of maps of individual cities to study the chronological development of urban design. More experimental have been attempts to compare alternative appearances: the appearance of a painting in alternative frames, alternative designs for the display of new exhibitions, or alternative appearances of paintings if cleaned or restored in different ways.(36)
Nearly all of these approaches are possible to some extent without computers. In most cases, pre-computer examples, executed manually, served as primitive prototypes for similar but more complex computer modeling. However, the time, effort, and skill required to reconfigure or otherwise modify images manually has discouraged all but the most dedicated scholars. Moreover, with such a commitment of time and effort, previous reconfigurations have been undertaken largely as demonstrations or for publication, with the outcomes largely predetermined. Without the ability to try out complex modifications experimentally, the possibility of new discovery has been largely absent. All this is changing fast. As new programs for 3-d modeling become more available, and as new types of modifications are invented, increasing numbers of scholars and students will experiment with them and discover new rewarding approaches to research and teaching.(37)
_ _ _ _ _
1. Michael Ester, "Digital Images in the Context of Visual Collections and Scholarship," Visual Resources, X, 1 (1994), p. 23. In this article, Ester provides the defining formulation for any consideration of the use of digital images for scholarship in the arts. For a previous warning about the complex interface between art historical research and electronic imaging, see Marilyn Schmitt, "Art Historians and the Computer: The Context for Electronic Imaging," Eva '92: Electronic Imaging and the Visual Arts: Conference Proceedings (London: National Gallery, 1992).
The best brief introduction to digital imagery, with excellent glossary and up- to-date bibliography, is Howard Besser and Jennifer Trant, Introduction to Imaging: Issues in Constructing an Image Database (Santa Monica, CA: Getty Art History Information Program, 1995); available also on the internet (http://www.ahip.getty.edu/intro_imaging/0-Cover.html).
A landmark, special issue of Visual Resources (Vol. X, No. 1, 1994), edited by Christine L. Sundt, was devoted to "Issues in Electronic Imaging"; a previous Special Issue (Vol. VII, No. 4, 1991, edited by Alan B. Newman, Deirdre C. Stam, and Christine L. Sundt, was devoted to "Electronic Visual Imaging in the Museum."
2. This article is heavily dependent on information and ideas already published by others, on notices, images and discussions posted on the computer internet, and on conversations with experts who have already implemented the use of digital imagery at their institutions, a number of whom have been kind enough to demonstrate their systems for me. I have attempted to credit these experts and institutions where appropriate in these endnotes, partly as sources for others pursuing digital image projects. I am especially in debt to the editors and authors of two journals that comprehend the field with professional standards: Computers and the History of Art and Visual Resources. Many, unknowingly, have contributed through the internet - it is difficult to imagine any non-computer subject related to art history on which one could become informed with so little effort. In Oregon, I have benefited from conversations with the growing ranks of computer experts, especially, over the years, from the advice and encouragement of Christine Sundt, Curator of Slides and Photographs in the Architecture and Allied Arts Library at the University of Oregon, and more recently at Reed from the help of Marianne Colgrove, Associate Director, Computing and Information Services.
This article originated in a report prepared for Reed College, which has pioneered the integration of computer technology at liberal art colleges and the use of computers for research and teaching. The college has supported my long-term interest in visual images as evidence, most recently with a summer grant from the Dean's Development Fund, which has made this article possible. For this, my special thanks to Dr. Linda Mantel, Dean of the Faculty and Professor of Biology, and to Martin Ringle, Associate Dean and Director of Computing and Information Services.
There is no pretension that this article contains anything new for those who regularly work with digital imagery, though I hope the perspective of an interested user may be of value to those involved in crucial decisions about such things as fair use, standards, and internet access. For my art history colleagues and students, for whom some of the potential uses of digital imagery may be new, I have made a special effort to use common language instead of the technical terms rampant in computer literature.
The argument of this article is not dependent on the state of digital image technology at any moment or on any particular projects. However, I have attempted to give references in these notes to a variety of persons, projects, publications, and organizations which may help readers in pursuing one or another aspect of digital imagery. These notes are in no way comprehensive but record only those leads that I have come upon, unsystematically, in writing this article, with the unfortunate limitations of my largely North American experience.
3. The Commission on Preservation and Access, an independent body sponsored by colleges, universities and related organizations to foster collaboration among libraries and allied organizations, has funded important studies on standards, copyright and fair use issues. An impressive list of available report and specialized studies can be obtained from the Commission on Preservation and Access, 1400 16th St., NW, Suite 740, Washington, DC 20036-2217 (AMathews@cpa.org). Many of their reports are available online from the Stanford Conservation OnLine Resources for Conservation Professionals (COOL; http://palimsest.Stanford.edu - now dead link).
Of special note have been the heroic efforts of the Getty Art History Information Program (AHIP), in collaboration with other institutions, to establish international standards and practices in the visual arts and humanities. Without these it would be impossible to document, store, access, and share the increasing overload of textual and visual information in the modern world. These multifaceted initiatives are described on AHIP's world-wide web site (http://www.ahip.getty.edu/intro_imaging/0-Cover.html).
4. Prominent among these has been Marilyn Aronberg Lavin, Art and Archaeology, Princeton University, who also serves as listowner for the Consortium of Art and Architectural Historians listserv (CAAH@pucc.Princeton.EDU). Her "Piero Project" and digital image projects of other art historians are cited, where appropriate, in later sections.
Archaeologists have been more active in investigating and using digital imagery. See P.M. Dew, et al., "Illuminating Chapters in History: Computer Aided Visualization for Archaeological Reconstruction," Papers Presented at the World Archaeological Congress WAC2, Barquisimeto, Venezuela, September 1990, ed. P. Reilly and S. Rahtz, Science and Archaeology, no. 32, pp. 20-27. See also P. Reilly & S. Rahtz, eds., Archaeology and the Information Age: A Global Perspective (London: Routledge, 1992).
Likewise, conservators and conservation scientists have been quick to investigate potential uses of computer imagery. For the most advanced uses in both archaeology and museum conservation, see the forthcoming proceedings of the international conference, "Imaging the Past: Electronic Imaging and Computer Graphics in Museums and Archaeology," held at the British Museum, 3-5 Nov. 1994. For annual summaries of the most technically advanced digital image projects for the visual arts, see the preliminary conference information and Conference Proceedings of EVA (Electronic Imaging & the Visual Arts), an annual conference, held each year, beginning in 1990, at the National Gallery, London.
5. In her 1994-95 annual report, Christine Sundt reports that the University of Oregon Slide Library circulated an average of over 200 slides per day for the calendar year, nearly 400 slides per day in peak months during the academic year.
6. For information on new art museum CD-ROMs etc., see ITEM (Image TEchnology in Museums and art galleries database), ed. Isobel Pring, pub. by the International Visual Arts Information Network (IVAIN, email@example.com), in assoc. with the International Documentation Committee (CIDOC) of the International Council of Museums (ICOM). For reviews of art CD-ROMs see Visual Resources: An International Journal of Documentation, ed. Helene Roberts, sponsored by the Visual Resources Association (VRA), review ed. Elizabeth O'Donnell. An annotated list of CD- ROMs available on art is included in a book scheduled for publication early 1996, Key Guides to Electronic Resources: Art and Art History, by Martin Raish (Medford, NJ: Information Today). Raish is Art Bibliographer, Binghamton University Library, Binghamton, NY (firstname.lastname@example.org).
7. The two most extensive programs with which I am familiar are at the Canadian Museum of Civilization, Hull, and at the American Museum of Natural History, New York. At the CMC, the Executive Director, George F. MacDonald (email@example.com), reported in May 1994 that, to date, over 200 master Photo CDs had been produced, holding more than 20,000 images, and that half a million analogue images were about to be digitized ("Dynamics of Culture and Identity, and the Potential of Interactive Technologies to Engage Users of Cultural Institutions," paper prepared for a panel session of the Cultural Technologies Convergence conference, Toronto, 27 May 1994). Also in 1994, William Weinstein (firstname.lastname@example.org), Systems Analyst for Research and Databases, AMNH, reported that the Anthropology Department was "halfway through a twenty-five year plan that includes . . . computerizing catalogue records, and the creation of an image database of the department's 1.5 million artifacts" ("Designing an Image Database: A Holistic Approach," Visual Resources, X, 1 , p. 49). He tells me that, as of Sept. 1995, they had completed photographing or rephotographing every Northwest Coast and Eskimo artifact in the ethnographic collection (the archaeology department is separate), totaling 18,000 objects, and digitizing every image on Photo-CDs at 3072x2048 resolution. These can be viewed at 320x240 resolution on the museum's internal network and, if necessary, at full resolution in the department. The museum intends to make these available on the World Wide Web, with the option of ordering a computer print or Photo-CD copy. They have now photographed about 7,000 of the remaining North American ethnographic objects, which will be available in the same way.
8. The Getty Conservation Institute is to be commended for its thorough recording of conservation projects in which it has been involved. The GCI houses an archive of c. 25,000 original 35mm slides of these projects, all carefully labeled and recorded in a database, and stored in over one hundred three-ring looseleaf notebooks. The images are now being scanned so that image and label information for each slide will appear on a single computer screen. Currently, the computer images are too small for anything but identification, but the original slides provide a veritable gold mine for research.
9. The same digitized image viewed on a video monitor, Kodak Photo CD player, or with an affordable digital projector will always be significantly fuzzier, with much less detail, than the same image viewed on almost any computer monitor. This may not matter for many uses, but fuzzy images are unacceptably limiting when one is attempting to study a work of art.
10. As a standard reference for degrees of resolution, it is helpful to use the five standard resolutions in which images are digitized on the widely used Photo CDs. Described in terms of the total number of pixels (a pixel, or picture element, is one dot) that we can see on the screen when we look at a digitized image, the five standard resolutions are 192x128, 384x256, 768x512, 1536x1024, and 3072x2048. A Pro Photo CD includes one higher resolution, 6144x4098. Kodak plans to make available one even higher resolution in the near future. Of course, where the monitor can display the full resolution of the image, the higher the resolution, the more detail we can see.
The digital image industry seem to be accepting the middle resolution as its standard. Advertisements for even leading CD-ROMs frequently refer to their images as "high resolution" and "superior quality" when they are only 768x512. An image at this resolution pixelates slightly at the first standard zoom. To be able to examine a digitized image of a work of art in detail, the resolution must be at least 3072x2048. A Pro Photo CD includes the six resolutions listed above. In this article, I refer to the lowest two as "low resolution," to the middle two as "moderate resolution," to the highest on a regular Photo CD as "high resolution," and to the highest on the Pro Photo CD as "extremely high resolution."
11. The classic study was Michael Ester's "Image Quality and Viewer Perception," Leonardo, Supplemental Issue 1990, pp. 51-63; republished in Visual Resources, VII, 4 (1990-1991), pp. 327-352. Ester rightly points out that "decisions about resolution and dynamic range are inseparable from the intended used of an image" (p.58). This being the case, conclusions based on viewing the full image lose relevance once we accept the fact that an important intended use is to examine details.
12. Scholars in other fields who discount art historians' need for high resolution digital images often revise their opinion when they are shown that one cannot read the text in digital images of medieval manuscript pages unless there is high resolution. Many beautiful manuscript pages, with illegible text, have been put on the itnernet. The Vatican and IBM are currently engaged in a joint project to digitize all the manuscripts in the Vatican Library at extremely high resolution.
13. Examples of high quality CD-ROMs are: Great Paintings, Renaissance to Impressionism: The Frick Collection (1994) and other CD-ROMs produced by Digital Collections, Inc., Alameda, CA; The Dresden Collection: Works from the Gallery of Old Masters (1994), Brueghel and Rubens: Paintings in Vienna (1995), and other CD-ROMs produced by Saskia, Portland, OR; and CD-ROMs produced to order by Art on File, Inc., Seattle.
On the other hand, paintings on the much heralded Microsoft Art Gallery: The Collection of the National Gallery, London (Redmond, WA: Microsoft Corp., 1993), so well conceived in many ways, pale in comparison with the National Gallery's own superb and reasonably priced 35mm slides. The award winning and otherwise deserving Perseus CD-ROM includes on its disk, in many cases, over 40 views and details of individual Greek vases, but precious few images on the computer screen that one would be willing to assign students for study (Perseus 1.0: Interactive Sources and Studies on Ancient Greece, Gregory Crane, ed. in chief [New Haven and London: Yale University Press, 1992]). A new edition with higher quality images has been promised for some time.
14. The distinction between "higher quality" and "fidelity" has been made by Michael Ester. Understandably, he writes that "Assessment of image quality is a statement about the image's fidelity to the source reproduction from which it is derived" ("Digital Images in the Context of Visual ollections and Scholarship," Visual Resources, 10 , p.16). However, for purposes of art history, we are concerned primarily with fidelity to the appearance of the work of art and would therefore favor correcting the color, etc. of the digital image while viewing the art rather than the image that was digitized. According to this standard, digital images can sometimes be made more "faithful" than the photograph, slide or transparency from which they were digitized.
15. See the publications of the Doerner Institute, Munich.
16. See David Saunders and John Cupitt, "Image Processing at the National Gallery: The VASARI Project," National Gallery Technical Bulletin, 14 (1993), pp. 72-85. Forthcoming: David Saunders, John Cupitt, and Helénne Chahine, "Longterm Colour Change Measurements: Some Results after Twenty Years," National Gallery Technical Bulletin, 17 (1996); Helénne Chahine, John Cupitt, Kirk Martinez, and David Saunders, "Investigating and Modeling of Colour Change in Paintings during Conservation Treatment," Imaging the Past (London, British Museum, c.1996). A similar facility, with more recent equipment, has now been set up at the Uffizi, Florence. See Vito Cappellini & Team, Florence University; Bruno Brunelli, Sidac, Italy; and Ron Cox, Time & Precision, UK, "The New Vasari Museum Laboratory System at the Uffizi Gallery & Colour Certification of True Colour Images," EVA'95: Conference Proceedings (London: National Gallery, forthcoming).
17. See Ian N.M. Wainwright, "Rock Painting and Petroglyph Recording Projects in Canada," APT Bulletin, XXII, 1-2 (1990), pp. 56-84; Ian N.M. Wainwright and John M. Taylor, "NRC's Laser Scanner for Recording and Replication," CCI Newsletter, No. 6 (Sept. 1990), pp. 6-9; and R. Baribeau, M. Rioux and G. Godin, "Recent Advances in the Use of a Laser Scanner in the Examination of Painting," Restoration '92, Conservation, Training, Materials and Techniques: Latest Developments, ed. Victoria Todd (Amsterdam, 1992), pp. 69-73. For further information, contact Ian N.M. Wainwright, Acting Chief, Analytical Research Services, Canadian Conservation Institute, Ottawa (email@example.com).
18. See Charles S. Rhyne, "A Slide Collection of Constable's Paintings: The Art Historian's Need for Visual Documentation," Visual Resources, IV, 1 (Spring 1987), pp. 51-70, esp. p. 67 and note 2; reprinted with additional illustrations in Art History Through the Camera's Lens (Gordon and Breach, 1995).
19. The most dramatic example is the recent CD-ROM publication Frank Lloyd Wright: Presentation and Conceptual Drawings (Oxford University Press and Luna Imaging, Inc, Venice, CA, 1995). This consists of one CD- ROM with small browsing images and documentation for nearly 5,000 Wright drawings, and three additional CD-ROMs containing higher quality, full-size images of each drawing. Such extensive material on a single artist provides students a visual feast in which they discover their own topics for investigation.
20. For the Museum Educational Site Licensing Project, seven museums are making available digitized images of works in their collections for copying onto seven university file servers. The following description of the project was posted to the Consortium of Art and Architectural Historians list (CAAH), 24 April 1995:
"This two-year collaborative initiative, launched in association with MUSE Educational Media, will develop methods and guidelines for the academic use of digitized museum-owned materials at colleges and universities. . . . Participating museums are: the Fowler Museum of Cultural History at the University of California, Los Angeles; The George Eastman House, Rochester; The Harvard University Art Museums, Cambridge, Massachusetts; The Library of Congress; The Museum of Fine Arts, Houston; The National Gallery of Art, Washington, DC.; and The National Museum of American Art, Washington, DC. Participating universities are: American University, Washington, DC.; Columbia University, New York, New York; Cornell University, Ithaca, New York; the University of Illinois at Urbana-Champaign; the University of Maryland at College Park; the University of Michigan; and the University of Virginia. . . . Museums participating in this pilot project will make digitized images and information, representing at least 3,000 works (500 from each participating museum), available to educational institutions in standard formats. The educational institutions will install these digitized images and descriptive texts on campus networks for research and education during the academic year 1995-1996. A minimum of 3,000 additional works will be added during academic year 1996-1997. . . . Images and accompanying documentation will be provided without site license or royalty fees during the project. . . . Once the two-year test is completed, images and information will be withdrawn from campus networks, unless subsequent licensing agreements are enacted to allow for continued use. . . . If you are interested in receiving further information about this project, please contact Jennifer Trant, Manager, Imaging Initiative, by phone (310) 451-6382, by fax (310) 451-5570, or by e-mail to firstname.lastname@example.org."
A few commercial slide companies, such as Art on File and Saskia, provide digital images of their original slides for copying onto institutional file servers, under site licensing agreements.
21. Columbia University is undertaking such a project for the short art history modules in their core curriculum, a required course annually taken by 800- 1000 students. The difficulty in attempting to make suitable images of works of art available to so many students at the same time, previous to the appearance of digital imagery, is illustrated by the fact that for this course digital imagery will be replacing University Prints. Stephen Murray, Professor of Art History and Director of Columbia's new Media Center for the Arts (currently within the Art History program), has previously made available hundreds of images of Amien Cathedral, with accompanying text, on the internet (http://www.arch.columbia.edu/DDL/projects/amiens/index.html). He tells me that summer 1995 he photographed the interior of Amien using a 15mm lens, for the QuickTime VR program which blends the individual images into a 360° panorama. He intends to demonstrate this at the annual meeting of the College Art Association in Boston, 21-24 Feb. 1996.
22. Peter Huenink, Associate Professor of Art, Vassar College, tells me that he and other art historians in the Department of Art at Vassar have for the past two years been putting some of their own research slides onto Photo CDs which students in their classes can check out at the library circulation desk and view on Kodak Photo-CD players or computer monitors. This use is in addition to the more common image bank ("pictorial reserve" at Vassar) created from the college's slide collection This has been facilitated by a cooperative arrangement with Eastman Kodak in Rochester. This project is budgeted through the library, where Thomas Hill, Art Librarian, has overseen the development of the project and facilitated an on-going dialogue about the pedagogic implications of digital image use in an academic setting (Thhill@vassar.edu). Although her slides are not yet digitized at high resolution, Kathleen Cohen, Professor of Art History, School of Art and Design, San Jose State University, San Jose, CA (email@example.com) has pioneered the use of digital images in both standard introductory art history courses and courses exploring potential uses of multi-media in art history. She tells me that in her art history survey course, ancient-medieval, using c.4000 digitized images of her own slides, each week she puts two groups of slides with her own accompanying text on a controlled institutional server (architectural images on the institutional web) for students to study on 17 inch computer monitors. These are digitized at moderate resolution in 24 bit color and students can zoom in to examine details. In her seminar size "Art History and Multi-Media" course, small teams of art history and technology students use her digitized images to create multimedia presentations on art history topics. Professor Cohen's pioneering use of digital imagery developed naturally out of her previous experience utilizing images on film or video disk.
23. The most advanced, university-wide system with which I am familiar is at the University of Maryland, where every room is wired, and, to date, 12,000 images have been digitized on Photo CDs. These can be viewed anywhere on the campus-wide system at 768x512 resolution, dithered down to 256 colors. Walter Gilbert, Associate Director of the University's Computer Science Center (Walter_Gilbert@umail.umd.edu), tells me that, in past years, teachers in a number of disciplines, but not art history, have used these images in the classroom, projecting directly from the university's image bank. This term, for the first time at Maryland (and perhaps anywhere?), an art historian, Sally Promey, Assistant Professor of American Art, is beginning to use digital projection in a regular art history class. These images are projected at 768x512 resolution and, when the computer is clicked, require only 3-4 second to appear on the screen. Dr. Promey tells me that she is using this system in an upper-level class of 15-20 students, in a classroom ("theatre") equipped not only with digital projector and screen but also with small individual monitors for each student, where the images are a bit clearer than on the screen. All of the digital images Dr. Promey is using are drawn from the images provided under the Museum Educational Site Licensing two-year experimental program.
24. The European Economic Community (EEC) is developing two telecommunications computer networks, one linking libraries, the other linking museums and technical partners. A Visual Arts Network for the Exchange of Cultural Knowledge (VAN-EYCK,http://www.bbk.ac.uk/Departments/HistoryOfArt/van_eyck.html - now dead link) will provide cross-library access to art history photographic archives and texts. It will link The Witt Library, Courtauld Institute of Art, London; The RKD (Rijksbureau Voor Kunsthistorische Documentatie), The Hague; Cruickshank-Glin Archive, Trinity College, Dublin; Birkbeck College, London; Utrecht University & Vasari Ltd. Telecommunications links to be used include EURO ISDN and academic research telecommunications facilities. A Euoprean MuseumsNetwork will provide cross-museum access to images of works in the participating museum collections with accompanying text. It will link museums in Lisbon, Madrid, Paris, The Hague, Bremen, Bremerhaven, Copenhagen, and Hamburg, and provide interactive multimedia access for museum visitors (Achim Lipp, "Towards The Electronic Kunst und Wunderkammer: Spinning on the European MuseumsNetwork EMN," Visual Resources, X, 2  , pp. 101-118).
25. See the excellent images at the worle wide web site for "A Hundred Digital Highlights: Koninklijke Bibliothek" (National Library of the Netherlands), The Hague (http://www.konbib.nl/100hoogte/hh-en.html). This was adapted for digital distribution from the book Honderd Hoogtepunten uit de Koninklijke Bibliothek/A Hundred Highlights from the Koninklijke Bibliothek (Waanders Uitgevers and Koninklijke Bibliothek, 1994).
26. For example, day-by-day photos and descriptions of the wrapping of the Reichstag in Berlin, by Christo and Jeanne-Claude, 17th-25th June 1995, were made available on the Internet (http://www.nbn.com/youcan/christo).
27. For a comprehensive review of the networking of images, see Richard J. Nees, Electronic Image Communications: A Guide to Networking Image Files (Medford, NJ: Learned Information, Inc., 1994).
28. A call for papers has been posted for a special issue of Visual Resources, guest edited by Robert A. Baron, Larchmont, NY (firstname.lastname@example.org) to discuss issues of copyright and fair use pertaining to images and related intellectual property.
29. Henry Gilmer Wilhelm, The Permanence and Care of Color Photographs (Grinnell, Iowa: Preservation Pub. Co., 1993), ch. 1, 6 and 18.
30. For example, the following announcement has recently been posted on the High Performance Computing Select News Bulletin (HPCwire), 23 June 1995: "Los Alamos, N.M. -- Four sets of encyclopedias could fit on an inch-long steel pin using a new information storage technique invented at Los Alamos National Laboratory. And future civilizations should be able to read the information etched onto the pins 5,000 years from now, without interpretive devices that convert computer data into language or pictures. The High-Density Read-Only Memory, or HD-ROM, uses a unique ion beam to inscribe information on pins of stainless steel, iridium or other materials that are built to last. An HD-ROM holds about 180 times more information than a comparably sized Compact Disc Read-Only Memory, or CD-ROM, today's cheapest data storage medium. Storage costs of HD-ROM are roughly one-half percent of CD-ROM costs. The HD-ROM should find immediate application in archival storage and data-intensive supercomputing, said developers Bruce Lamartine, a physical chemist in Los Alamos' Materials Science and Technology Division and Roger Stutz, a database and graphics engineer in the Nonproliferation and International Security Division. . . . 'The HD-ROM marks a complete departure from existing data storage technologies,' Stutz said. 'For the first time, a non-magnetic, non-optical data storage system can be made from truly robust materials.' . . . Since the medium isn't magnetic, electromagnetic fields can't destroy the data on HD-ROMs, unlike computer hard drives. . . . For binary data, the HD-ROM can describe in a human-readable format the instructions needed to read the data. For letters, numbers or graphics, the reader can recover visually apparent characters directly. . . . digital storage media are much more vulnerable than stone tablets or even printed documents. Magnetic fields, oxidation, materials decay and various environmental factors can erase digital information. 'HD-ROM is virtually impervious to the ravages of time whether from material degradation due to thermal or mechanical shock or from the electromagnetic fields that are so destructive to other storage media,' Lamartine said. The high cost of storage forces many organizations to discard valuable data. Stutz said NASA often is forced to get rid of satellite data and images that aren't immediately useful, even though the information might be of great future value. . . . he and Lamartine already have talked to film industry representatives about how to use the ion beam writer to preserve movies from Hollywood's golden age. For more information, contact Jim Danneskiold of Los Alamos National Laboratory at 505/667-1640, 667-7000 (email@example.com)."
31. See Janice Mohlhenrich, ed., Preservation of Electronic Formats & Electronic Formats for Preservation (Fort Atkinson, WI: Highsmith Press, 1993); and Jeff Rothenberg, "Ensuring the Longevity of Digital Documents", Scientific American (Jan. 1995), pp. 42-47, though digital storage experts have objected that Rothenberg severely underestimates the physical lifetime of digital magnetic tape.
32. The QuickTime VR program, recently developed by Apple, allows one to produces a 360° panorama of the inside of a room, blending together in a seamless image individual stills taken from a stationary tripod at the center. The viewer operating the computer can then pan to right or left at her/his own pace, and to some extent up or down. This program requires (if one is using a 28mm lens) that a minimum of 18 stills be taken at regular intervals, with the camera in a vertical ("portrait") position. If one wishes the viewer to be able to see higher or lower portions of the room, the stills must be taken with an even wider-angle, rectilinear lens, such as 15 or 18mm. Computer viewing of a full 360° rotation of sculpture can also be produced by fixing a camera to a stationary tripod and turning the sculpture on a rotating platform. For this, a minimum of 36 stills, taken every 10 degrees are necessary. For higher portions of the sculpture to be viewable on the computer monitor, one must take additional series of 36 stills.
33. For computer-based technology in the fields of building technology and historic preservation," see the excellent recent special issue of the APT Bulletin; the Journal of Preservation Technology, XXVI, 1 (1994). Beginning with this issue, the editor has introduced a regular column on computer based technology.
34. The most impressive of these yet developed is "The Piero Project," recently renamed *ECIT* (Electronic Compendium of Images and Text), developed using a Silicon Graphics IRIS VGX workstation by Marilyn Aronberg Lavin, Department of Art and Archaeology, Princeton University (MALAVIN@pucc.Princeton.EDU) and Kirk D. Alexander, Manager, Interactive Computer Graphics Laboratory, Princeton University (KIRK@Princeton.edu). Based on this database, in 1994 and 1995, Lavin and Alexander taught a one semester, interactive computer course for art history students. They conducted the class in a room in which the teachers and students each have workstations, and in which images were studied and created, texts consulted and written, questions asked, answers given, and discussions carried on entirely with computers. Information about *ECIT* with demonstrations can be viewed on their homepage (http://mondrian.princeton.edu/art430). They now hope to cooperate with other scholars in testing other materials with the system they have developed.
For a book now in press, Jeruselem, 600-1100 (Princeton University Press), Professor Oleg Grabar, Institute for Advanced Study, Princeton University, worked with two graduate students to reconstruct three stage in the growth of the city using computer imagery. The book will include plates reproduced from the computer images. Professor Grabar, Muhammad Al-Asad, and Abeer Audeh authored a ten minute video, Jeruselem, 600-1100 (1993, unpublished) demonstrating the use of 3D imaging in their study. The video allows one to see the reconstructed, abstract 3D forms of the city design and of major buildings from continually changing perspectives, with Grabar mentioning a few discoveries revealed by this process.
The Montréal Research Group (GRM/MRG) at the Canadian Centre for Architecture, Montreal, are using digital imagery to study the urban development of 17th to early 19th century Montreal. The results were first presented in an exhibition with accompanying publication, Opening the Gates of Eighteenth-Century Montréal, ed. Phyllis Lambert and Alan Stewart (Montréal: Canadian Centre for Architecture ; distrib. MIT Press, 1992). The techniques used in mapping the evolving city, incorporating massive quantities of detailed information, is explained in an unpublished paper by Léon Robichaud and Jennifer Waywell, "Mapping the Built Environment of Montréal: Issues for Two and Three-Dimensional Representation," presented at the Canadian Historical Association Annual Meeting, Calgary, 14 June 1994. "The most innovative feature of our approach, is the ability to reconstruct the town automatically at any point in time. . . . This sequence is not created from a series of static slices but rather, as we move along the time-line, the computer continuously accesses the database to select and display those features that existed on each and every day" (p. 17).
Color illustrations of a convincing computer reconstruction, by Victoria I, of the House of the Tragic Poet in Pompeii, were recently published in an article in The Art Bulletin (Bettina Bergmann, "The Roman House as Memory Theater: The House of the Tragic Poet in Pompeii, LXXVI [June 1994], pp. 225-256). Bergmann notes (footnote 64): "'Walk-throughs' of Pompeian houses via computers were offered at the recent show funded by IBM: Rediscovering Pompeii, Exhibition by IBM-ITALIA, exh. cat., ed. B. Conticello, IBM Gallery of Science and Art, New York, 1990". Although the walk-through at the exhibition was a completed demonstration for the public, it was the outgrowth of digital image research, for which see Rediscovering Pompeii, Ministero per i Beni Culturali e Ambientali, Soprintenza Archeologica di Pompei (L'Erma di Bretschneider, 1990), throughout, but especially pp. 104-127.
35. The most impressive virtual reality art environment I have seen is that of the tomb of Nefertari (Valley of the Queens, western Thebes, Egypx; 19th Dynasty, reign of Rameses II, 1290-1224 B.C.). This was "created in 1994 for the exhibition Nefertari: Luce d'Egitto, . . . at the Palazzo Ruspoli in Rome, October 1994-June 1995. Custom software for the application was written by Infobyte [Roma] under the direction of Dr. Francesco Antinucci of the Istituto di Psicologia, Consiglio Nazionale Ricerche. . . . source materials [provided] by the GCI and the Museum Egizio in Torino. Using a joystick, the visitor can travel in the tomb in an interactive, real time mode and experience the site [with stereoscopic vision] both as it appeared at the completion of the GCI Nefertari conservation project (1986-1992), and [to some extent] at the time of the tomb's discovery by Ernesto Schiaparelli in 1904. The visitor can also stop to look at a number of conservation problems and treatment methods, or to listen to recitations of hieroglyphic inscriptions that appear on he walls. . . . A three dimensional computer model of the tomb was produced using solid geometry modeling techniques. Images of the wall paintings were then mosaiced together and incorporated into the model to reproducer the interior surfaces as they appeared in 1904 and 1992 respectively. Virtual lighting sources were then placed inside the computer model" (GCI fact sheet, Feb. 1995).
It is important to question what we learn from even this excellent production that cannot be learned from the exemplary publication Art and Eternity: The Nefertari Wall Paintings Conservation Project 1986-1992, ed. Miquel Angel Corzo and Mahasti Afshar (Getty Conservation Institute and Egyptian Atiquities Organization, 1993), which includes full-page color perspective views of the interior of the tomb.
An article in the current issue of Archaeology reports on an exhibition, "Virtual Pompeii," to be shown at the de Young Museum from September 15, 1995, through January 7, 1996, followed by showings at other museums. The author of the article, Jane Vadnal, is art director of the "Virtual Pompeii" project. She tells me that each viewer, using a joystick and wearing headphone and goggles, will be able, for ten minutes, to move through Pompeii at her/his own pace, deciding what direction to turn, what buildings to enter, what sculpture or frescoes to view, and which peddlers, tradespeople, or priests to approach. Those of us who have not worked with virtual reality projects will be interested in effects such as changing shadows as the sun moves overhead and the morphing of sound from Latin into English as we approaches the inhabitants. Intriguingly, a decision had to be made about our height as viewer. Because ancient Pompeiians were shorter than 20th century Americans, the designers had to decide whether we were to approach the inhabitants face to face, as their contemporaries, or from slightly above, as 20th century visitors,
"The exhibit was created by the Virtual Reality Lab. of the Studio for Creative Inquiry at Carnegie Mellon University in Pittsburgh, a group that also created a walk-through of an Egyptian temple shown at the Guggenheim Museum in New York in 1994. The production is cosponsored by the Archaeological Institute of America and Silicon Graphics, a maker of computer hardware and software" (Archaeology 48 [Sept.-Oct. 1995], pp. 67, 69-70). Carl Loeffler is Project Director of the Virtual Reality project.
36. At the Art Institute of Chicago, Alan Newman, Executive Director, Imaging & Technical Services, Art Institute of Chicago (firstname.lastname@example.org) has joined with Frank Zuccari, Executive Director, Conservation (email@example.com), in making use of digital imagery to help in considering alternative treatment of paintings. Newman has produced a 9 1/2 minute video, "Electronic Imaging: Cleopatra; ' With Open Eyes' CD-ROM, Imaging and Conservation" (Art Institute of Chicago, 1994; unpublished), primarily for a lay audience, demonstrating electronic imaging projects carried out at the Art Institute. These include assembling an infrared mosaic, simulating the cleaning of a painting, simulating a drawing's original appearance, previewing framing options for paintings, clarifying x-ray images, and researching the attribution of a painting. Newman and Zuccari have produced an unpublished report, "Digital Imaging Methods in Conservation," on their collaborative project.
37. Following the completion of this article, two volumes of selected papers from an especially informative conference were published, including authoritative reports on the most advanced uses of digital imagery by museums: Multimedia Computing and Museums and Hands on hypermedia and Interactivity in Museums; Selected Papers from the Third International Conference on Hypermedia and Interactivity in Museums (ICHIM '95, MCN '95), San Diego, California, October 9-13, 1995, ed. David Bearman (Pittsburgh: Archives and Museum Informatics, 1995).
Charles S. Rhyne is Professor of Art History and Chair of the Department of Art at Reed College, Portland, OR (firstname.lastname@example.org).
In 1989 he served as art history chair for the annual meeting of the College Art Association in San Francisco. He is an internationally recognized Constable scholar and has had a long-term interest in visual images as evidence. Recently he has lectured and published on the philosophy and practice of conservation and in June gave the keynote address at a symposium on "Conservation and cultural diversity" at the J. Paul Getty Museum.