It uses purple-colored ink.
Could be automatic or hand-cranked.
Makes many copies very quickly (the faster you crank the faster the copies would come spitting out).
I think it’s called some kind of “transphotofabricator” or something like that… … .
You are thinking about a “spirit duplicator”, made by many companies, including Ditto, so it was often called a ditto, just like we say “a xerox copy” today. It used an alcohol to wet a master, usually made with a purple dye, that transferred the disolved dye to each copy until it ran out (200 copies was typically max, IIRC).
The Mimeograph used true ink, usually black, and squeezed it thru a “stencil”, quite similar to silk screen printing. The number of copies was limited only by how long the stencil would last before shredding from a buildup of friction. I don’t know how many copies this might have been, maybe in the thousands?
Does anyone remember the gelatin process? Similar to spirit duplicator in chemical concept, it stored the dye on a rubbery gelatin base and each copy had to be squeegied to the gelatin, then peeled off. Slow, and 50 copies max, and each one a little lighter than the previous one. I like my laser printer much better, but those were the days, oh, you kid!
Musicat, I see that I’m not the only olde school copy-squad dude on the SDMB! Kudos to you, my friend, for pointing out the difference between mimeograph and spirit duplicators.
For more about how the processes differed, see my post in this olde thread:
Correct or not, many people referred to the spirit duplication process, or any process involving a hand cranked duplicator as a “mimeograph”. The only one I remember having anything to do with produced the purple copies, and were undoubtedly “spirit duplicators”, but I don’t think I ever heard them called anything but “mimeograph” machines.
Y’know, it doesn’t bother me (too much) that there are adults who have never used a mimeograph, but that the name has already faded from memory makes me feel really old.
I never thought about that – to me the processes of gelatin and spirit duplicators were different, but perhaps the chemical process was the same.
I remember a shallow, square pan, slightly larger than a 8.5x11" sheet of paper, with a thin gelatin layer in it, and a cover. You opened the cover, placed the master on the gelatin surface, squeegeed it down, then removed it. The reverse image was left behind, and transferred to each blank sheet that was subsequently placed on the surface, then peeled off. When done, you would lightly wash the surface, being careful not to leave drops of water behind, which would permanently pockmark it, then cover the pan and let it sit for a while – hours to days.
It could then be reused, as the image had faded, soaked deeper into the gelatin, and spread out enough that it no longer mattered.
I even had a mass-quantity machine, with a canvas belt strung between two rollers like a scroll. The belt was coated with perhaps an eighth-inch of gelatin on one side. When you were finished with one part of the belt, you rolled it to one side, exposing a page’s worth of new surface for the next master. High-volume copying!
I never thought about that – to me the processes of gelatin and spirit duplicators were different, but perhaps the chemical process was the same.
I remember a shallow, square pan, slightly larger than a 8.5x11" sheet of paper, with a thin gelatin layer in it, and a cover. You opened the cover, placed the master on the gelatin surface, squeegeed it down, then removed it. The reverse image was left behind, and transferred to each blank sheet that was subsequently placed on the surface, then peeled off. When done, you would lightly wash the surface, being careful not to leave drops of water behind, which would permanently pockmark it, then cover the pan and let it sit for a while – hours to days.
It could then be reused, as the image had faded, soaked deeper into the gelatin, and spread out enough that it no longer mattered.
I even had a mass-quantity machine, with a canvas belt strung between two rollers like a scroll. The belt was coated with perhaps an eighth-inch of gelatin on one side. When you were finished with one part of the belt, you rolled it to one side, exposing a page’s worth of new surface for the next master. High-volume copying!