Harrison Eiteljorg, II
(See email contacts page for the author's email address.)
The CSA Propylaea Project has been completed, and the materials have been made available on the web. The last of the materials to be put on the web were the photographs. This was not accidental. It was difficult to determine how best to present the photographs of the structure that had been taken during the course of the project -- or in some cases many years earlier. The photographs were numerous, amounting to about 450, a small number for a long-running excavation but a rather large one for such a concentrated project.
Our first responsibility was archival; archiving the original photo files is a requirement of any archaeological project. It is necessary to preserve the original files because they represent the true record; anything done to such a file for the purposes of access or storage may have obscured something of value. Even changing the file format from one lossless format to another should ideally be avoided so that future users have available to them the closest thing possible to what the camera "saw." (Note: Some years ago many photographs taken with 35 mm. slide film were scanned at high resolution. An argument could be made that the slides should be archived, and, were that possible, I would include the physical slides in the archives. However, there are precious few institutions prepared to care for such materials properly, and finding one that can archive both the slides and the digital materials is effectively impossible.)
Providing access to the archival files was one of the most clear problems we faced as the project was concluding. However, the user who needs access to the original files will be rare indeed; so providing simple, direct access to the archived original images seemed not to be required. Furthermore, we decided to provide access to the archival originals only after direct contact between a potential user and those responsible for the archives, a process that would begin with the same email or postal-mail process no matter where the files reside or how they have been archived. (Obtaining the images may be relatively easy once the information required has been shared. For example, the archival files might simply be on the web in a directory protected from automated searches and without a simple and obvious interface. A potential user could then be given the procedure for finding the files and the system for naming them to gain access to individual images. Nevertheless, the process would begin with communication to obtain authorization.)
Access to the archived originals is thus possible at any time, not necessarily with ease but without undo effort. Access to the images for more routine use was a more pressing need. Although the originals will be so rarely consulted that they need not be available without direct communication between user and archives, the scholar interested in this material will need direct, easy, web access to good, high-resolution images that may aid in one or another scholarly pursuit as soon as possible. (Of course, those images will also be the starting point to permit a scholar who has found a useful image to go back up the chain to the original to see if more information can be gleaned from it.) Providing that level of imagery -- good, high-resolution, easily-accessed images -- presented many problems.
The problems are not at all unusual for the CSA Propylaea Project, but it seems worth reviewing the problems and the chosen solutions for the value of the example.
A few basic facts:
Determining the disposition of these photographs has used up a great deal of time and much discussion; some light may have been generated along with the heat. It will, I suspect, be a constant problem for some years until we in the archaeological community have decided how to deal with photographs. The issues seem reasonably simple. How do we provide scholarly access to the best possible images (the highest resolution) without permitting unauthorized use? The solutions, unfortunately, are not so simple.
Given the foregoing, the issues boil down to a small number.
The choices are not numerous, and they are not either surprising or innovative. Some of the choices have been signaled in the discussion above. They are certainly not in any sense the only solutions that could have been reached. In addition, we certainly do not believe that these choices should be expected to be appropriate for any length of time. We are still too close to the beginning of the digital era to be able to divine approaches to last for long, and the pace of change is too fast.
First is the issue of compression. That turned out to be a rather easy issue to deal with. Moderate compression seems to present no problems. Compression does not impact resolution, which can remain high, permitting details to be seen. We have decided to use compression level 5 (as noted above, with 1 being the most compression and 12 the least.) Absent compression, the files are simply too large for serving on the web unless resolution is greatly reduced.
Second is resolution. It would be simplest to say that we will use the highest resolution possible, relying on compression to compensate and keep the file sizes within reason. In fact, serving full-resolution images will work with all our images because the highest resolution is only about 2000 x 3000 pixels. Were there significantly higher-resolution images, a different choice might have been required to prevent outlandish file sizes.
The third question is the method of presentation. If we use JPEG images embedded in standard web pages (HTML pages) or served as images only, any user can see the images directly and quickly, but the choices for zooming in and out are not as good or as intuitive as with other tools. In addition, the image files can be very quickly moved onto another computer. On the other hand, if a label or watermark is part of the image, the file has some protection even in the JPEG form, since removing either a label or a watermark would demonstrate clearly a user's intent to violate the copyright.
Images could also be embedded in PDF files at any resolution, and PDF files are now routinely downloaded and displayed directly in browsers, making them little different from JPEG files. In addition, this is a choice with two important benefits: 1, the images can be conveniantly examined at any level of detail either in the browser or in a program devoted to reading PDF files, and 2, PDF files can be locked so that the images in them cannot be extracted easily. The locked PDFs, however, do not provide certain protection, but anyone wishing to violate the copyright would need to do so very intentionally, as with JPEG labels or watermarks.
Putting these pieces together, we have the following:
A thumbnail image to be used as a finding aid. The small size makes them useless for most other purposes, and compression renders them even less useful for any other purpose. This choice required no debate.
A compressed JPG with a label or watermark or a compressed JPEG imbedded in a PDF file as the web-accessible image. This is not an answer but an either-or. So which should it be? We decided on the compressed JPEG with a label, but the reasons are not truly compelling. A different choice may be made by others or as time marches on. Because I was able to automate the process of creating labeled and compressed images from the originals (via AppleScript and by virtue of having the requisite information in a FileMaker database), that seemed a good choice. A watermark could have been added as easily, but a visible one might have been problematic in terms of the utility of any particular image, especially with an automatic process locating the watermark. An invisible one would add cost and complexity. In addition, the PDF-creation added a step that seemed to offer few, if any benefits. Preventing improper use is probably as well accomplished by adding the label as by using a watermark or putting the image into a PDF, and use of JPEGs on the web requires nothing but a standard web browser.
Original, full-resolution, unaltered, archival images available only on request.
Even this process has required more time and trouble than is ideal, especially since I had to learn enough AppleScript to accomplish the automation (and some of the script commands changed when I upgraded the MAC to "Snow Leopard"). However, it should satisfy scholarly needs, both immediate and long-term ones, providing good information for any user. In addition, of course, we will preserve the "raw data" represented in the original photographs. Now if we could just find an archival home for these materials.
-- Harrison Eiteljorg, II
1. The image has been taken down as a result of my objection, but the owner of the site complained on the web site's home page that, "This website was created to help fellow art students but because of complaints about copyright I have decided that it is not worth continuing." While I have no idea what other complaints he had from other people whose images had been taken, there is a huge difference between putting up links or even the images themselves with proper attribution and putting them up as one's own. If he expects sympathy, he will not get it from here. Return to text.
An index by subject for all CSA Newsletter issues may be found at csanet.org/newsletter/nlxref.html; included there are listings for articles concerning the use of electronic media in the humanities, articles concerning The ADAP and issues surrounding digital archiving, articles concerning The CSA archives, and articles concerning The Propylaea Project.