Lantern Slides

A. K. Christensen

In the early days of biological electron microscopy (in the 1950s and 1960s) it was standard practice to prepare electron micrographs for projection in lectures as 3-1/4 x 4" lantern slides. It was felt that 2 x 2" projection slides were too small to transmit the detail and quality that was necessary for electron micrographs. As a consequence, giving a lecture required two different projectors, one for lantern slides and the other for Kodachromes or other 2 x 2" slides. By about 1970 it had become apparent that the slight resolution benefit of lantern slides was not worth the pain of having to deal with two projectors during a lecture. So everyone switched to using only 2 x 2" slides. I threw away almost all of my lantern slides, but kept a slide box containing some of my favorites. Of course, in the 1990s the 2 x 2" projection slides were all replaced by digital images in PowerPoint. The present PowerPoint shows digitized images of the old lantern slides that I kept.