The CSA Propylaea Project

Harrison Eiteljorg, II, 2013

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Harrison Eiteljorg, II
Center for the Study of Architecture
Box 60
Bryn Mawr
PA 19010

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Final Report, CSA Propylaea Project: What To Do About Photographs

Please note: As the CSA Propylaea Project ceases active work and prepares to place its materials on the web, the images are a particular concern. This document has been posted to serve as a request for comments about how best to deal with those images. Please contact CSA Director Harrison Eiteljorg, II with your thoughts, criticisms, and suggestions. The point is to generate the best possible system for sharing images from the CSA Propylaea Project on the web.

To communicate with Mr. Eiteljorg, please either send email to him using the user name nicke with the domain name or telephone him at 484.612.5862. Email comments will be reported here, and it is very much hoped that this document will evolve as readers offer their thoughts and help guide us to a better system.

The number of photographs taken in the course of the CSA Propylaea Project has been enormous. We have not made it into the thousands but not for want of trying. There are some hundreds of images.

The images range from the mundane — a single block in one or another wall photographed from close-range and showing little of interest to anyone other than a serious scholar — to the ridiculous — various of us bundled up and huddled together as if to go skiing while at work on the Propylaea in the winter of 2003. On the other hand, there are more traditional photographs of the building, of salient details, and of the work in progress.

CSA will assert a copyright on all the images (in some cases partly on behalf of a photographer who has given us the images to use but who deserves to have control over their use outside the project). Asserting a copyright and having it honored, however, are not equivalent, and that is one of the issues that complicates presenting images on the web. We want people to use them, after all, but finding one, as has been the case, on someone else's web site (not by link, but the image there) complete with an asserted copyright by the owner of that site is, however appalling, neither a complete surprise nor easily prevented. [Note: The Archival preservation of the photographs relieves CSA of any need to assert a copyright. The photographs have become subject to the copyright rules and procedures of the Archaeology Data Service. This document was written far in advance of the archival arrangements; the concerns expressed had to do with the CSA Propylaea Project website at]

As a result, the CSA Board has spent considerable time debating the best way(s) to present the photographs on the web site. Those already "up" have been presented via what we believe to be a very good interface — a map of the Propylaea showing points of view, with each point of view linked to pages with thumbnails of the photographs from the particular point of view. The thumbnails lead, in turn, to "VGA" or "XGA" images on the site (640x480 or 1024x768). It is those final images about which we are concerned. When the resolution is not sufficient for a scholar, we promise to provide original, full-resolution images, but what can we honestly say about the longevity of any plan to provide access to higher-solution images in the future? Furthermore, if the high-resolution images are buried on a server somewhere, out of sight until some scholar has found the right person to ask for access, of what value are they? Not being sure that there is a robust approach for long-term storage, we are seeking a better answer, both for those who want better images now and for those in the future who will need the best images we have.

Some issues and points for discussion:
  1. The number of images that might be used in a paper publication without authorization is extremely small, probably not even a dozen.

  2. The number of images that might be taken for use on another web site is larger, much larger, but by no means likely to exceed a relatively modest number, say 50. And one hopes that, over time, fewer and fewer people will try to fool people into thinking a given image is theirs and honestly link to the original pages with the images instead.

  3. Scholarly use of the images — the use that most certainly requires high-resolution images — should not be unduly difficult. After all, making the images available to scholars is one of the points of the CSA Propylaea Project and its web site. And serious scholars may well want the highest resolution available to answer a specific question. Indeed, absent the high-resolution images on the web, we would have to provide a way for scholars to get to them via request. Being sure any system for doing that will outlast those of us involved is impossible.

  4. Compression of the image files seems an acceptable thing to do, especially since it improves access by reducing file sizes. The JPG compression algorithms do not provide lossless compression; so there will be some degradation of the images. However, our experiments indicate that JPG compression level 5 (with 1 the most compressed and 12 the least) provides more than adequate results; images compressed to that extent are still very good. By and large the color palette is limited, making compression less damaging. Such compression makes it both easier to serve high-resolution images because of the smaller file sizes and marginally less likely that the images will be used in a paper publication. [Thanks to Tom Reynolds for pointing out the confusing language here previously. I hope this is more clear. It seems inherently confusing that the smallest number for compression yields the most extreme compression.]

  5. One unusual way to serve images suggested itself to us when we examined the work of the Archaeological Research Institute (ARI) at Arizona State University. The older propylon material previously available via this site is now at the ARI site (, and the images have been provided in the form of PDF files with the full resolution of the original image. (This can be accomplished easily, and the resulting PDF files contain the images at full resolution — complete with the usual zooming capacity for enlarging the image and moving about within it. The PDF files are not significantly larger than the image files they contain.) Since the images may be extracted from the PDF files, there is no security against improper re-use or even paper publication. In the case of the older propylon, so few of the images might be used commercially that the problem is a non-problem. However, that may not be the case for the more important and more photogenic Propylaea.

  6. PDF files can be "locked" so that the image contained therein cannot be extracted; in that case the PDF file is not itself protected, but the underlying image cannot be removed for independent use. However, there are software tools that permit unlocking locked PDF files, and a screen-capture program would permit using an image taken from a screen, yielding a lower-than-maximum resolution but nonetheless a resolution more than adequate for many purposes.

  7. It is possible to place a watermark or visible copyright statement on each image before incorporating it into a PDF file.

  8. Using the locked PDF format permits one to provide good images for use and somewhat less good ones for publication (due to compressing the images before putting them into PDF files). It also protects them from easy re-use, though, as noted above, the protection is of limited value. On the other hand, this process may be more helpful for re-use on the web since making new versions of the underlying images is more time-consuming and those who grab images for unauthorized re-use on the web tend to be interested in the quick and easy.

  9. Any process that requires an unauthorized user to make conscious steps to overcome protection makes that user's intention to steal someone else's property clear. For instance, for someone to remove an image from a PDF via one or another mechanism is by no means impossible, but it's so clearly an illegal act that it would be simple to show intent if necessary for protecting the image.

  10. Using PDFs also lets us put on the web one file per image instead of the two currently used — and the PDF carries the full resolution of the original.

  11. The idea of a copyright statement on the image is a good, simple approach that can be used with the PDFs. The problem here is that doing that requires each image to be treated separately to be sure the note is close enough to the center to prevent easy removal via cropping and yet does not obscure anything important. Otherwise, the process can be automated.

  12. At the end of the day, how much time and trouble is this worth? We don't want to to see the images improperly used, but neither do we want to spend a lot of time, effort, and/or money to develop a plan to prevent something that is not terribly likely — particularly since whatever we do will probably only work only for a few years until the next great toy makes its mark on the web.



About this document:

  • Title: "Final Report, CSA Propylaea Project: What To Do About Photographs
  • Author: Harrison Eiteljorg, II and the staff of CSA, Box 60, Bryn Mawr, PA 19010, (e-mail: user nicke at (@) the domain; tel.: 484-612-5862)
  • Original file name: photothoughts.html
  • Revision history: Since this document is part of the Final Report, changes should not occur. Serious mistakes may be corrected; if so, clear indications of corrections will be included. First posted: 14 September, 2000. Last updated (formatting only): July, 2012. Prepared for ADS archival storage June, 2013.
  • Internet access: This document was first prepared for, operated by the Center for the Study of Architecture and Harrison Eiteljorg, II. It has been turned over to the Archaeology Data Service for archival preservation.
  • Long-term availability: This document or its successors will be maintained for electronic access indefinitely.