Stereo PDF's for UC Berkeley Optometry

We have done so much work over the years digitizing slide collections used to teach art and architecture history, so it was fun to be approached by forward thinking faculty from another discipline.  In this case, it was Dr. Wayne Verdon, of the U.C. Berkeley School of Optometry. It was a familiar story, slides are scratched and fading, hard to replace, slide projectors have been discontinued, and students want electronic access to materials. But this project presented a new technological twist: the subject of the slides, human eye retinas, had been photographed with a stereo camera, so there were two slides for each retina. By viewing matching pairs of 35mm slides through stereo viewers, students could see the eye in three dimensions.  

The challenge for us was how to scan these slides, and present them on a computer screen in a way that would provide the same three dimensional effect required to teach students now and into the future. We solved that problem, with a lot of testing and guidance from Dr. Verdon, by scanning the slides at very high resolution on our Hasselblad X5 scanner, maintaining precisely the same magnification on all the scans, and then compositing each stereo pair into a single canvas in Photoshop.  The trick was figuring out what spacing to use between the 'eyes' so that, when viewed with 3D glasses, they appear three dimensional.

This is an example of one of the final composited pages. We delivered each set as a PDF file, so they can be viewed on any computer screen or tablet. We also provided a set of the layered TIFF files used to make the composites so they can modify the type, and even the spacing if needed, in the future.