SOME USES OF A VIDEO CASSETTE RECORDER IN THE CONSERVATION LABORATORY
Alexander Katlan, Barbara Appelbaum, & Paul Himmelstein
ABSTRACT—Several uses for a video cassette recorder are presented: in conservation surveys (using a video camera), in conjunction with an infrared vidicon camera, and in the detailed documentation of the surface condition of large works of art.
THIS SHORT ARTICLE contains several informal notes on the use of a video cassette recorder in two conservation practices. Unlike many other “high-tech” tools used in the field of conservation, the video recorder is a household appliance designed for the technically unsophisticated. Because of this, technical issues like the accuracy of color rendition or high resolution of the image, usually of primary importance in conservation work, are not a major consideration. Video tape does not in any way replace traditional photographic work in the conservation laboratory, but provides a method of recording and storing large amounts of information quickly and easily. We are reporting on our experiences in the hope that it will encourage other conservators to investigate further uses of the VCR in the conservation lab and in museums.
1 THE USE OF THE VCR IN CONSERVATION AND OTHER COLLECTION SURVEYS
TWO OF US (Appelbaum and Himmelstein) about two years ago purchased a video cassette recorder and video camera for use in conservation surveys. The choice of equipment was made primarily on the basis of cost and ease of use, although we specified that we wanted to be able to use the camera in low light levels, and we wanted a macro lens. The equipment was very helpful.1 With no additional lighting in dimly-lit storage rooms and exhibition galleries, we could quickly record all the pieces surveyed, with as many views as we wanted, and with details of areas of damage using the built-in zoom lens. For pieces like large or complex sculptures, the use of the VCR provides more information than almost any number of still photographs. Our informal comments, keyed to the needs of the survey, were also recorded on the tape, along with any identifying information. When helpful, we referred to a list we had previously prepared containing the categories of information we wished to note. This is sometimes important, as in many surveys it is impossible to go back to pieces seen previously to record missing information. The video tape allowed us to record a great deal of information and store it in a compact way.
Our basic procedure in doing surveys on tape is to examine each object first and discuss our findings. When we are ready to record, one of us holds the object, moving it as necessary for the picture. This person reads the accession number and condition notes aloud onto the tape, and points out areas that would benefit from close-ups. When relevant, we include the reverse of paintings, the inside of vessels, problems caused by mounts, etc. For pieces where only one still photograph is required, the tape is run only for the length of time it takes to record our commentary. The second person holds the camera and reads numbers from the footage counter in the camera so that they can be written onto our list of objects. Our copy of the final survey report includes the index numbers so that the images can be retrieved easily. For our own use, we also keep written notes of condition on lists provided by museum staff. If a survey were to be done with only one conservator, a quick-witted museum staff member would be drafted for help in handling the objects.
When writing the survey reports in our own laboratory, we compile a list of objects with basic notes on condition and proposed treatments from our written notes, and then refer to the tape for further details. The use of our computer, a Macintosh, in writing these reports is vital, since the outlines of reports can be typed, and then details added as the tape is viewed or as decisions are made about treatment recommendations and costs. As with audio tape, writing a lengthy report without written notes is quite awkward and time-consuming, and would be particularly difficult without a word processor.
The tapes have proved useful long after the survey report was written, in refreshing our memories about pieces that we were preparing to treat, and on changes in condition that might have occurred between the time of the survey and the time we were asked to treat a piece. In one case, the tapes also became a possible source of comparison in a collection where insect infestation was suspected. We expect at this time to be able to specify which pieces have more flight holes since the survey was completed.
One of the main advantages of video tape is that the images are instantly available, without the time and expense of film development, choosing negatives, making prints, identifying the objects, labelling the prints, and storing them in a way that permits easy retrieval. For the same purposes, the only bookkeeping needed for video tape is a written list of the objects recorded on each cassette, and, if necessary, the index numbers noted on reports. A small cassette holds information on a large number of objects. With at least two hours of tape on a cassette and a minimum of a few seconds' scan for each object, several hundred pieces can be recorded on one tape. Although for condition and treatment photographs, and for permanence of the image, video tape is no substitute for photographic prints, for many other purposes it is a very efficient tool.
Another use of a video tape scan is to record details of the surface of large paintings. One eight-by-ten inch photograph of a large painting makes details unreadable. Taking same-scale photographs over the whole surface in order to construct a mosaic is very difficult. Scanning with the video camera is very easy. For paintings, particularly abstract ones, which are travelling, the video tape scan allows comparison with either the actual painting or with photographs of possible damage in transit. The tape helps to answer the frequent, and aggravating, question: “Was that there before?”
Other potential uses of the video camera include instant comparison of a piece or a small area of a piece before and immediately after certain treatment procedures. For example, it is sometimes helpful when filling losses in paintings or objects to have an image of the unfilled area for comparison. For outdoor sculpture or building surveys, video tape would be extremely useful. The use of video tape in educating conservators by recording treatment techniques, educating trustees about museum problems, or educating museum staff about conservation concerns could also make it a powerful propaganda tool.
In addition, it is becoming more clear that many museums lack photographic records of their collections. Although prints of individual pieces are certainly the preferred medium, video tape records can be made in very small amounts of time, with less hazard to the collections from being moved to photographic studios, heat from lights, and handling. We are currently recommending to our institutional clients that they consider creating a video tape record of their collections. For purposes of evidence in case of theft or damage, for use by curators in-house, potential borrowers, or visitor/browsers, such a tape would be extremely valuable.
We recently experimented with the use of VCR in conjunction with transmitted and reflected infrared scanning of a number of paintings.2 The results were quite successful and the process was greatly simplified over still photography.
2 THE USE OF THE VCR AS A METHOD OF RECORDING INFRARED IMAGES
THE TRADITIONAL METHOD of recording information from an infrared vidicon unit is to photograph with a conventional film camera directly from the television monitor. This method has the advantage of producing black-and-white prints and negatives. One disadvantage is a loss of focus around the edges of the photograph because of geometric distortion due to the curvature of the screen; a number of institutions have purchased a monitor with a flat screen to compensate for this problem. In addition, the recorded image is not immediately available.
Overall scanning, from edge to edge, of a painting has to be done frame by frame and results in the construction of a photographic mosaic. The process of making a photo-mosaic has its own problems: difficulty in matching the image at the edges of the prints, and differences in density of the prints. The difference in density is partially caused by the IR camera which automatically adjusts the image as it moves from light to dark. The result is that the mosaic, which is extremely time-consuming to construct, is difficult to read.
In using a video cassette recorder for recording infrared images, the output of the infrared camera is hooked directly into the video recorder. A painting was examined first by infrared, and decisions were made about exactly what to record. The actual process of recording went very quickly; the examination and recording of infrared images of about a dozen paintings were made within one afternoon. With experience, the whole process could go much faster.
THE VIDEO RECORDER we use is a Quasar VP5435wQ VCR. The camera is a Panasonic WV-3230/8AF with auto-focus, zoom and macro lens. The video tape records in color, although the playback through the camera monitor is black-and-white. The final color rendering is not perfect by any means; it would be possible to improve this by re-balancing the color more frequently during use, and by increasing the light levels. Our VCR contains a rechargeable battery pack, and can record six hours of tape without an outside power source, so that surveys can be done outdoors, or in other areas without the need of plugging into an electric outlet. No special lights or lenses were used; the equipment was used in exactly the same way as it would be by a home hobbyist. Most such recorders have similar features, like “freeze-frame” capability, date and time that can be recorded on the image, automatic focus, a zoom lens, etc. We would not necessarily recommend our equipment over any other, although we are completely satisfied with it. New equipment, smaller and lighter, comes out every year, and ease of use is a primary consideration.
The infrared equipment used was a Dage MTI 65 MK2 video camera, with a Schott infrared filter #RG850 with a 50 mm. Canon macro lens. The infrared tube was made by Hamamatsu, model no. N214-01, and the monitor was an Audiotronics model, with 800 lines horizontal resolution. A quick trip to an electronics store provided the necessary adapters for the hook-up. The VCR is hooked up directly to the output of the Vidicon system, and the image appears on the monitor as usual. When the VCR is activated, the image that appears on the screen is recorded on video tape as well.
4 ADVANTAGES OF THE VCR
- Large numbers of images can be recorded easily, with no need to move objects to a photographic studio. The pieces can be moved during recording, so that the total amount of information recorded is much greater than with any number of still photographs.
- The ease of operation and speed of recording allows a great deal of information to be recorded without interruption of the survey process. For use with infrared, the speed of recording makes it possible to record as a routine every painting that is scanned, including those which appear to have nothing of interest. There is no need to interpret images before deciding what to photograph. When paintings by a particular artist are being studied, even the absence of underdrawing on IR can be a useful piece of information.
- A voice recording can be recorded simultaneously with the recording of the image to identify the object and to explain what is being shown.
- A library of visible light and infrared images, similar to the libraries of x-radiographs that many museums have, can be easily built up. A great deal of information can be stored on one cassette, particularly compared to the space required to store corresponding numbers of photographic negatives and prints.
- A whole tape can be duplicated commercially, or with two tape machines.
- It is easy to compare a “freeze-frame” image on the monitor with a photographic print.
- It is a simple matter to include on the same tape an image of the artifact under normal illumination, or under raking light. For some legal purposes, it may be important to include a photograph of the painting being turned around to read the inscription. A single still photographic print may provide a reading of an inscription, but does not in itself indicate what painting it came from.
- The main disadvantage is that no hard copy is produced. However, at worst, the conservator has almost exactly what he would have had before, that is, an image on a monitor screen. Images can be chosen and photographed at any time, with only slight loss of quality. When necessary, as for inscriptions, photographs can be taken for a client. For purposes of research, we feel that it is more important in most cases that the private conservator or the museum laboratory retain a permanent record than that the client or curator have infrared photographs. Because of the rapid developments in technology, the direct production of highquality still prints from a video tape will undoubtedly soon become possible.3
- Viewing requires a video tape player and a monitor. This is getting to be less of a problem, since many museums already use video tape in their education departments and therefore have monitors, and many people own tape players. (Extensive use of video tape in the conservation laboratory may make the purchase of a monitor, i.e. television, advisable. This may lure curators into the laboratory during important events, like the final game of the World Series. It is not clear at this time whether this should be seen as an advantage or disadvantage.)
- During the infrared scanning process, the VCR records the slight vibration and temporarily out-of-focus image produced while the camera is moving. This can be eliminated by turning the VCR on and off, or by stopping the camera periodically to record a still image.
- The resolution of the video tape image is never more than and usually less than that produced by the camera.
- Questions have arisen about the permanence of video tape. For our purposes, this is not a problem. For museums or laboratories interested in using electronic recording media for long-term records, hard disks appear to be preferable.
- Comparison between infrared images on video tape would require duplicate tapes and two monitors.
The video cassette recorder may be a complex piece of electronics, but it is, after all, a non-scientific household appliance. The ease of use makes it applicable for many purposes where traditional photographic methods are too time-consuming or too difficult. We would like to encourage conservators to experiment and report on other uses.
BarbaraAppelbaum, PaulHimmelstein, “Planning for a Conservation Survey,” Museum News64, no. 3, (Feb. 1986), pp. 5–14
This use has been suggested previously: William A. Real, “Infrared reflectography at the Cleveland Museum of Art: Paintings, Objects, Manuscripts,”AIC Preprints, Washington, D.C., 1985, pp. 79–89, and personal communication with Donald K. Beman, Associate Director, Beman Galleries, Nyack, New York.
Computer programs for microcomputers which produce digitized images from video sources, allowing a print to be made on a printer, are now available. At present there is considerable loss of quality, but this will no doubt improve.