I remember these from junior high. The paper was tissue thin and the copies were pretty terrible. As students we dreaded getting tests or class material from these worthless copiers. I can’t recall what the technology was called.
I worked in the school office in 9th grade. I got in trouble for ruining a loaned piece of sheet music with one of these copiers. There was this carbon pack thing that you put the original in. You ran it through this copier and the tissue paper copy could be separated from the carbon pack.
I loaded the original sheet music into the carbon pack backwards. It came out of the machine covered in black waxy toner and ruined. The music teacher raised all kinds of hell because it was a loan from some place.
Mimeographs were purple, and the copies came out on basically regular paper. (Plus, if they were fresh out of the machine, they had that awesome mimeograph smell. :D)
Possibly this was some sort of thermal-paper copier thing?
ETA: Never mind! Apparently the classic smelly purple copies were from Ditto machines. Mmm… ditto machine copy smell.
I used two different things, one was the purple mimeograph machine mentioned earlier, and the other made better copies. It used a multipart thing that had a green waxy later. I think it was called a spirit something.
It sounds like the alternate process to xerography that I remember from the 60s and 70s. I think Xerox had the patent lock on their process and this was about the only other type of machine that was marketed. The process was like you described, but for the life of me I can’t remember what this was called. It was the only low cost single copy alternative method to Xerox until their patents ran out.
ETA: I don’t think it was a spirit printer. Like a mimeograph, the odor is the most memorable thing about those.
I remember Gestetner machines. I looked them up and found they were similar to the mimeograph in process. Also called cyclostyle, which was an alternative term used at school.
They produced a black printed sheet without the characteristic smell or purple print of the spirit duplicator, which I can’t for the life of me remember what we called. It may have been banda machine, as in the UK.
The ones that produced purple copies is called a spirit copier (although we all called it a stinky), but entirely different since you had to produce a master copy. You did this by typing (or writing) and the master which was backed by a kind of dried purple ink. You then ran it through the machine, which brushed some solvent (that stank) on the ink and transferred to paper, which was not especially thin. It could make, oh maybe 100 copies before it got too thin to read.
Then there was the mimeograph. Again, you needed a master. You typed on it and the act of typing nearly went through the master, leaving only a thin membrane. The ink went through the membrane and on to the paper. Later there was a way to make a master by some sort of process that would duplicate a document fed through it. I have no idea how that worked.
The thing to recall is that all these processes produced copies for a fraction of a cent a page while xeroxes were 10¢ a copy which is more like $1 today (you didn’t buy the machine, they were rented at low cost and you paid Xerox for each copy).
When the cost of photocopying came down, all those other machines disappeared. Good riddance.
I well remember producing exams with handwritten stinkies. Before that we would write exams on the blackboard.
We used to make copies on those back in my father’s store; it was a proprietary system from 3M. Schools rarely had them, and used spirit duplicators for short runs (they were only good for a small number of copes – around 50 IIRC) and mimeographs for longer ones.
3M was trying to compete with Xerox, whose patents for plain paper copies prevented anyone else from using them. Once the patents expired, 3M ditched the thermal copiers; the plain paper were better in just about every way.
You’d expose the tissue paper to light, and then run it through the heat roller to create the image. But if you did it backwards, it just wouldn’t make a copy; it didn’t ruin anything.
Thank you! Thermofax is the name I was trying to remember. They produced very, very thin paper copies. That would easily curl. We hated those copies in our school orchestra. They wouldn’t stay straight on our music stands.
Good point about handwritten tests. A lot of my teachers hand wrote tests on those spirit copier masters. I guess it was quicker and more convenient than using a typewriter. I kind of liked the personal touch of a handwritten exam.
We always took the purple master from the thermofax machine and put it on a spirit duplicator machine and ran regular paper copies. I was very adept at running the thermal masters through old Apple dot matrix printers- that worked better than using the thermofax machine.
BTW, the copy machine brushed the paper with the solvent which then got rolled over the master sheet with the waxy ink. Get a drop of solvent on the master and it would run like crazy, ruining it.
I remember calling those “stencils”. If one would type on that thin tissue-paper-like stuff, you had to remove the ink ribbon from the typewriter, but some typewriters had a setting which would just disable the ribbon. That way, the key would strike the paper directly, and cause some breaks in it, and if you were lucky, the paper would stay intact, leaving a stencil for the ink to pass through later. (And if you weren’t lucky, the middle would come out of an “o” or an “e”, so that the ink would fill the middle.)
Typing errors could be corrected by painting some correction fluid onto the paper, and it filled up the holes and made the paper intact again. (Not “White Out”, this was a special clear paint designed for these stencils.)
We usually used these for typewritten work, but theoretically one could use a stylus to make handmade stencils. It was difficult to avoid tearing the paper, though, so we did that only if we really had to, like for the diagrams on a geometry exam.
Wikipedia is great! Read the article here to relive other memorable trivia about the Ditto machines. I had forgotten, for example, that although purple was the most common color, many other colors were available, and they could all be used on a single master. This made it a very low-tech (read: dirt cheap) way of creating multi-color output in a single pass.
Good point, I never realized that. BTW, a bit of scotch tape on the back of the master would prevent that bit from copying. So you could erase errors and even write over them since the ink would stick to the tape too.