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Direct Digital Image Capture:
Current Practices and Problems

Charles Rhyne
Reed College

Report of a Workshop
held at the Rochester Institute of Technology, 21-24 Sept. 2004
published in Visual Resources: An International Journal of Documentation, Vol. XXI (June 2005), pp. 214-219.

 

Conference

As institutions switch from film to digital photography, how can they produce the most accurate, reliable and useful images of the works in their collections? This was the central question at a recent conference at the Rochester Institute of Technology. Over one hundred representatives of nearly fifty institution and nine companies met September 21-24, 2004 at R.I.T. to hear presentations, see demonstrations, and discuss this question. This article is a report on and critique of that conference.1
The conference was held toward the end of a fifteen-month project, funded by the Andrew W. Mellon Foundation, to “document current practices, develop a testing procedure to quantify image quality, perform the test at . . . representative museums, and hold a workshop and disseminate the results.”2

Survey

To document current practices, a survey was conducted of digital imaging procedures currently used at American Museums, Libraries, Archives, and other cultural institutions. Over forty institutions submitted answers to the questionnaire. Because no comparable survey has been conducted, the results should be of considerable interest to cultural institutions, indeed to anyone interested in high quality digital photography.3

       The survey forms were to be filled out by “those responsible for the photography department at [each] institution.” The survey forms included 77 questions in all, including detailed questions regarding the personnel involved, training and attitudes regarding digital photography, imaging workflow, and about each institution's specific practices in the use of digital photography, such as studio setup and equipment, image editing, color management, and maintenance of image files.4 As one might expect at this early stage in the adoption of direct digital photography, there was considerable spread in most of the answers. Some of this spread undoubtedly resulted from institutions having used more than one system or software package as new options became available. This diversity is surely not all to the bad, since the more real-life experiences on which we have to draw the better. Nevertheless, it was surprising to find so many color management software packages having been used and such a range of hardware and software used for calibration of the display. It was a bit disturbing to see that different institutions reported such different points at which initial sharpening first occurred in their workflow (12 institutions before printing, 9 other, 6 reporting “highest quality digital master image is sharpened before saving,” 3 at capture, and 2 do not know). Likewise, it was disturbing to see that only 49% of responding institutions archive the original raw file from the camera; that, of the responding institutions, 1 stored the digital masters in GIF file format, 5 in Photoshop, 7 in JPEG, and only 39 in TIFF; and that 8 of responding institutions backup their images on tape, 8 on DVD, 11 on CDs, and only 12 on other systems (presumably including the most archival storage, servers and hard-drives).

       Perhaps of more long-term importance than these recent technical differences were the different approaches noted by responding institutions. Only a few of the questions focused on differences in approach, but these answers were surprisingly varied. In answer to the question, “Which of the following statements best describes your definition of image quality?”: 46% selected “the image on the screen looks like the original”; 15% selected “specified values for a target are matched in the digital file”; 8% selected “the measurements on the output device match the measurements on the original”; 8% selected you have an aesthetically pleasing reproduction on the display”; 8% selected “you have an aesthetically pleasing printed reproduction”; and 15% selected “other”. In the discussion also, it was clear that some institutions archive digital images primarily for publication in books or other formats, while others believe that the archived image should be use neutral.

       For some of us, the choice most in need of further investigation is the complex question of how the various types of reproductive images can most accurately “look like the original.” In the questionnaire, there were three questions about the type and placement of light for viewing reproductive images, but none about the conditions for viewing the original works of art. In recent years, lighting of paintings in museum galleries and photography studios has been quite flat.

Site Visits

In addition to the survey, site visits were conducted by the R.I.T. team to six major early digital image adopter institutions, with return visits to four.5 Although answers to the questions regarding studio set-up and equipment were not included in the printed results distributed to conference participants, these were described in presentations by the R.I.T. team and by representatives of the site-visit institutions. Here again the range of studio set-ups, lighting, cameras, and lenses was surprising. Our first reaction might be to question the lack of consistency among institutions, but, at such an early stage in direct image photography by museums, the range of practice has been natural and the range of experience informative. One large, well funded museum has purposely purchased a variety of cameras and lenses as major changes have taken place and has tried out different lighting and copy set-ups as a way of becoming familiar with the options and making informed decisions.

       The differences noted at the visited institutions also depended on the history of digital adoption at each institution and on the uses for which digital photography has been carried out. In some cases, institutions began digital photography for small, individual projects; in others as a large campaign to digitize entire collections. In some cases, digital photography is carried out specifically for posting on the web, in others primarily for print publication in catalogues, in others primarily for high quality archiving, in others largely for collection management.6 At one institution, at least, the specific use for each shot is identified and the digital photography is carried out to achieve this. Of course decisions have also been influenced by the nature of the material being photographed. Libraries are much more likely than museums to batch process images after studying a representative sample.

       The R.I.T. team performed various systematic comparisons of photographic methods at the visited institutions, attempting to quantify each comparison. These were described by Erin Murphy and will be included in her master's thesis, currently being completed at the Munsell Color Laboratory at R.I.T.7 Perhaps the key comparison presented and available for inspection in the laboratory was a comparison of the digital images produced by each of the four revisited museums from two monitor size, multicolored paintings, each institution using its standard equipment and procedure. The colors of the standardized prints of the four resulting digital images varied enough in color to make the R.I.T. team and other conference participants concerned about the color accuracy of current museum procedures. Less surprising, for both paintings the color of all four of the prints varied somewhat from that of the original paintings when viewed next to each other. One should note that the visited institutions were full participants in this process, each welcoming the R.I.T. team members for a full day of tests and experiments.

       A central goal of the R.I.T. project is to devise a way to produce more consistent and more accurate images of works of art, which would also allow institutions to dispense with the costly and time-consuming process of post-capture visual editing. To pursue this, Roy Berns and his colleagues have been experimenting with spectral imaging, identifying the optical properties of a painting's materials, representing a work of art by its spectral data rather than how it looks to the viewer or to the camera. Because of the limitations of current museum practices, a major project to develop a spectral imaging camera is underway, co-sponsored by R.I.T., the National Gallery of Art, Museum of Modern Art, and the Andrew W. Mellon Foundation.8

Original Works of Art

It is important to note that this highly promising spectral-art-imaging project aims to make possible more accurate images of original works of art, not simply more accurate images of printed reproductions or other images. This is, of course, a vastly more challenging undertaking.

       The aura of the “original work of art” has become an almost mystical concept. In the final analysis, there is surely an aspect of this experience that cannot be explained; but some essential characteristics of original works of art put special demands on any attempt to achieve their direct digital capture. Unlike reproductions in books or on monitor screens, original works of art have highly complex surfaces, and these complexities convey important aspects of each work's meaning. Even if we set aside architecture, with its size and encompassing volume, and sculpture, with its complex 3-dimensionality, we need to recognize the ways in which the 3-dimensionality of paintings makes for an experience different in kind from that of reproductions. The term “direct digital capture” is perhaps misleading, suggesting as it may a digital replica.

       As we view paintings (the focus of the R.I.T. project), we do not hold our heads still or move them from left to right, in and out, but in an unconscious fluid motion, exploring whatever we find of interest: the astonishing detail in a renaissance portrait, the gently moving clouds in an impressionist landscape, the vigorous energy of a Picasso abstraction. The inquisitive nature of this viewing process, for pleasure and discovery, and in the case of research often to answer specific questions, is central to our experience of art. If the painting is small, we may even hold it in our hands, turning it near a window, to examine it more thoroughly. As we view a painting in this way, our angle of view changes, as does the angle of light falling upon it, altering the colors and reflectivity of the different paints and revealing the expressive impasto of the painting's surface. The artist's hand comes alive, allowing us to relive the process of creation and to feel the artist's response to his subject.

       In viewing reproductions of paintings, even reproductions of small paintings that can be reproduced exact size, even reproductions of the highest quality with near facsimile color, the complexity and expressive quality of the surface is largely missing. Several institutions have been carrying out research to find digital equivalents for these characteristics of original works of art, but the challenge is much greater than the ability to record the optical properties of a painting's material, remarkable as that achievement surely is.9

       One aim of the R.I.T. project is to develop procedures to “quantify image quality.” But the concept of “image quality” depends on the information we desire to record, the purpose of the imaging, and the uses to which the images will be put. At the conference there was an especially instructive discussion about the background desirable for photographers at art museums. Some favored hiring technical specialists, though others felt that a background in commercial photography and lack of an art background resulted in sterile images, insensitive to the individual works of art. Some favored hiring those with art backgrounds, though others felt that this turned the images into new works of art.

       At the conference, representatives of a number of institutions described the importance of capturing and archiving extremely high quality images of each painting only once, to provide for all future derivative uses, so that the costly and time-consuming digital capture process would not have to be repeated. Although this has been an effective argument in obtaining funding for digital projects, it seems to many of us an impossible goal. No matter the quality of any current digital images, experience teaches that there will be new types of digital imaging, different not only in quality but perhaps also in kind, that will become the new standard for high quality reproduction and advanced research.

       In spite of abundant evidence to the contrary, the concept of a single iconic image of each painting pervades the publishing world and to a large extent even the teaching of art history. But not only do works of art look different when displayed in different environments with different lighting (underscored by the R.I.T. team and accommodated for in their tests) but works of art themselves change. Even if we again set aside architecture and sculpture, exposed to the elements and other intrusions, paintings also change, more continuously and more significantly than is recognized outside the conservation world. Paintings are damaged and deteriorate. Paints fade, colors change, different colors change in different ways altering the relationships among areas of a painting, dirt accumulates, varnishes darken. It remains common practice for paintings to be cleaned and touched up as they pass through commercial galleries, in accordance with the taste of the time, to make them more saleable. Paintings are restretched, relined, and reframed. Museums clean and restore their paintings. For museum records and research, it is necessary to record these changes, and for exhibition catalogues it will be necessary to publish images comparable to what is displayed on the walls. Re-photography will continue to be a necessary fact of life.

       The sharing of current practices in the R.I.T. survey and on-site tests and the sharing of ideas at the conference provide, for the first time, reliable information about the state of high quality digital photography at American institutions. It is clear that commonly held benchmarks do not currently exist. It is also clear that institutions have different concepts of what they hope to achieve when imaging their collections. Institutions are attempting to address these differences, and a major project to develop a spectral imaging camera is underway. Much work remains to be done to achieve images that convey the types of information available when viewing original works of art

Notes

1. The conference was titled “American Museums Digital Imaging Survey Benchmarking Conference: Direct Digital Image Capture of Cultural Heritage in American Institution.” A brief description of the conference, with links, is available at http://www.cis.rit.edu/museumSurvey/conference.html.
Principal investigators at R.I.T. were Roy Berns, Munsell Color Science Laboratory, and Franziska Frey, School of Print Media; assisted by Mitchell Rosen, Center for Imaging Science; Lawrence Taplin, Munsell Color Science Laboratory; and Erin Murphy, graduate student at the Munsell Color Science Laboratory. Other presenters, involved in one way or another with the project, were Francesca Casadio and Christopher Gallagher, Art Institute of Chicago; Peter Burns and Don Williams, Eastman Kodak Co.; Andrew Gunther, Harvard University Art Museums; David Remington, Harvard University Libraries; Barbara Bridges, Metropolitan Museum of Art; David Mathews, Museum of Fine Arts; Eric Landsberg, Museum of Modern Art; Alan Newman, National Gallery of Art; Ricardo Motta, Pixim Inc.; and Günter Waibel, Research Libraries Group, Inc.

2. See http://www.cis.rit.edu/museumSurvey/research.html. For a report on a closely related conference, also sponsored by the Andrew W. Mellon Foundation, and the National Science Foundation, see http://www.dli2.nsf.gov/mellon/report.html.

3. Although the survey period is now over, the survey questions can still be viewed at http://www.cis.rit.edu/museumSurvey/survey_noSubmit/intro.php. The survey is titled “Direct Digital Capture of Cultural Heritage: Benchmarking American Museum Practices and Defining Future Needs.” The finished report, including compilation of answers to the survey questions, is expected on-line and in print toward the end of 2004.

4. Although this review does not include consideration of administration matters such as staffing and funding, it should be noted that, at the conference, there was widespread agreement that the single greatest imaging need at most institutions was an institution-wide image management system.

5. Site visits were conducted at the Art Institute of Chicago; Harvard University Art Museums, Harvard University Libraries; Metropolitan Museum of Art; Museum of Fine Arts, Boston; and the Museum of Modern Art.

6. The R.I.T. project and conference focused on digital imagery and were not intended to address the comparison with film-based photography. For example, in the survey questionnaire, question 19 read “Has your institution started using digital photography? If NO, you have completed the survey; thank you;” without asking “why not?” Nor were there any questions about how institutions were handling their film based photography, although the director of photography at one major museum stated that the most important recent step taken by their museum for photography was to put their film based photographs into cold storage. A few advantages of film based photography were mentioned at the conference: the advantage of retaining a hard copy back-up (especially desired by conservators), the convenience of having all material on each object in a single file folder (especially desired by curators), and the much less costly process of archiving film based photographs (see http://jodi.ecs.soton.ac.uk/Articles/v04/i02/Chapman/, with link to a full-text PDF, documenting comparative storage costs). There was some discussion of the financial advantages of converting entirely to digital imagery versus maintaining the option of film-based photography where it retained advantages for some museum functions.

7. Erin Murphy's thesis is titled "A testing procedure to characterize color and spatial quality of digital cameras used to image cultural heritage." Her March 15, 2004 document “A Review of Standards Defining Testing Procedures for Characterizing the Color and Spatial Quality of Digital Cameras Used to Image Cultural Heritage” is available as a full-text PDF.

8. See http://www.cis.rit.edu/museumSurvey/news.html, with link to a pdf announcement.

9. For architecture, see for example http://www.cvrlab.org/research/research.html#publications.
For sculpture, see several of the chapters in Exploring David: Diagnostic Tests and State of Conservation, ed. Susanna Bracci, Franca Falletti, Mauro Matteini, and Roberto Scopigno (Firenze: Ministero per i Beni e le Attività Culturali, 2004.

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