American Scientist

In the course of preparing lectures based on the material in my books and columns, I developed during the closing decades of the 20th century a good-sized library of 35-millimeter slides. These show structures large and small, ranging from bridges and buildings to pencils and paperclips. As recently as about five years ago, when I indicated to a host that I would need the use of a projector during a talk, just about everyone understood that to mean a Kodak 35-mm slide projector (or its equivalent), and just about every venue had one readily available. Nowadays, when I say I will be showing slides and will need a projector, just about everyone assumes that I will employ a PowerPoint presentation, and that what I need is a digital projector. Indeed, the conversion from physical to digital "slides" has been so rapid and complete that the Eastman Kodak Company ceased manufacturing its classic projectors late last year and has let it be known that it cannot guarantee that parts or service will remain available after 2011. Thus, the once-ubiquitous 35-mm slide projector will soon become a museum piece.