A popular reminiscence going around the image blogging platform Tumboleer about overhead projectors has reminded me of my favorites.
I attended a county college (AS/AA granting) for my high school education and also to get the 2 year degree after that. After that I transferred to a 4 year institution and got my BS there. For various reasons, the county college professors were highly invested in the use of overhead projectors for their course lecture.
To my memory there were multiple different makes and models going around the classrooms, ranging from the hideously cheap to the built-like-tanks. My particular favorites were the 3M models (since given up on), the red font 9200 and the white font 9800. There were others that had more rounded cases, but these were blocky and angular and reminiscent of old IBM PCs in their unadornedness.
The 9200 and 9800 differed in, if I remember correctly, depth of the case and also the internal arrangement of the lenses and halogen bulb. The one big annoyance with these was the bulb changer. Being high end devices, they had two bulbs in each box. If one burned out (which was indicated by a little red × over a bulb icon lighting up) you could switch to the next… by using an incredibly hard to turn dial. The force (torque) you needed to develop around this little plastic (maybe 2 cm) dial was almost impossible. We (professors and myself) would instead open the case and physically push the wire arm that the dial controlled to the proper position instead.
As you would expect from a seriously sturdy affair like the 9800, it was heavy as anything. I remember carrying one from the Engineering building to the Art building the one time I remember one being used at college getting my BS. It must have weighed at least 15 to 20 kg.
Now adays the trend is for PowerPoints, which I don’t entirely disapprove of. I’m just sentimental about old matter like this, that reminds me of past professors. Goodbye, Professor Sollimo, goodbye.