Opaque projectors were awkward, but actually not as heavy as they looked, since they were mostly hollow. These delightful machines allowed faculty to project virtually anything they found, if it would fit in the projection area. They were primarily used to project print materials. There were some problems -- they tended to use lower power lamps (bulbs) in order not to damage the material under the light, but this meant the room had to be virtually lightless before the text would be clear. Most rooms had enough light leakage from doors and windows that the projected material was blurry from any distance. However, they are still useful in the health sciences for a very narrow and specific purpose, for which nothing else will do quite as well. In cardiac or emergency care, when you have a paper strip from a heart monitor, this is still one of the easiest ways to show that readout to the entire care team at once for purposes of case presentations.
Abstract | History | Timelines | Memories | Future | Gallery | Credits