Some people called the PowerPoint slide precursors transparencies, but they are really foils. From the French feuille. And those suckers got HOT.
@Cosmichomicide These were still in use when I was in school. In one of the labs where I worked, there was a computer display which sat on top of one of these to be projected on the big screen. It was primarily used by the other labbies to play Net Trek.
The memories !!
, the transparent computer screen thingy that goes on top of a projector !! 😀
our school still used these in the late 2000'S
So, here's a bit of carbon dating for you.
I first personally used one at IBM and made the mistake of calling them transparencies while DRAWING on one with those nasty little markers. I got a lecture AND sent to the appropriate link in the GIANT algorithm dictionary (it was IBM, after all) to learn the proper name and the history.
Clearly, I am still scarred by more than the molten lava heat of the lamp in that thing.
@Cosmichomicide I'll take your word for it. My professional path has led me away from presenting, as I intended. I hadn't laid eyes on an overhead projector in years, and it brought back that memory. Like mimeo, a technology which was ubiquitous in my life until it wasn't.
@Cosmichomicide When I was in the first grade, we had an arithmetic test where the mimeo was so bad that the teacher told us that if we weren't sure what the numbers were, we should write in what we thought they were and solve for that. I got bored and filled in more numbers then there were. She was impressed that I answered the resulting problems correctly, but gently scolded me for being imaginative in interpreting her instructions. This set the tone for much of my succeeding education.