In the 1982 movie Fast Times At Ridgemont High, a classroom of students receives a set of paperwork to pass backward. Nearly every student in the room takes a big whiff of their sheet before setting it down. If you know, you know, I guess, but if you don’t, keep reading.
Those often purple-inked papers were fresh from the ditto machine, or spirit duplicator. Legend has it that not only did they smell good when they were still wet, inhaling the volatile organic compounds within would make the sniffer just a little bit lightheaded. But the spirit duplicator didn’t use ghosts, it used either methanol (wood alcohol), isopropyl, or, if you were loaded, ethyl alcohol.
Invented in 1923 by Wilhelm Ritzerfeld, ditto machines were popular among schools, churches, and clubs for making copies of worksheets, fliers, and so on before the modern copy machine became widespread in the 1980s. Other early duplicating machines include the mimeograph, the hectograph, and the cyclostyle.
Getting A Handle On Duplication
To use the ditto machine, one would first make a master copy using a special sheet of paper with a special type of waxy ink on the back that dissolves in alcohol. These types of sheets are still around today, in a way — if you’ve ever gotten a tattoo, you know that they don’t usually just freehand it; the artist will draw out your design on special paper that they can then use to lay down a temporary tattoo on your freshly-shaved skin before going for it.
But don’t get too excited; tattoo transfer sheets aren’t compatible with ditto machines for a number of reasons. As I mentioned, ditto sheets use alcohol to transfer the ink, and tattoo sheets use heat and pressure. They’re too thin for the mechanics of the ditto machine’s drum, anyway.
So once you’ve typed or drawn up your master sheet, you’d mount it on the drum of the ditto machine. Then, with a big crank handle, you’d roll the drum over sheet after sheet until you had what you needed. The average master could make roughly 50 to 500 copies depending a number of factors.
The rise of higher-quality master sheets is largely responsible for this wide range, but there are other factors at play, like the color that gets used. Purple was made from a dye called aniline purple and lasted longest on paper, although there was also green, red, and black. You see a lot of purple dittos because of its vibrancy and the fact that it was highly soluble in alcohol.
The type of paper entered into the equation as well: absorbent paper like newsprint would make fewer copies than smoother, less porous bond paper. And, as you might imagine, dense text and images used more ink and would wear out the master faster.
As with many paper-based things from decades ago, the durability of dittoes is not so great. They will fade gradually when exposed to UV light. Although there is no citation, Wikipedia claims that the average ditto would fade in direct sunlight after about a month. It goes on to assume that most ditto machine users printed onto low-quality paper and will eventually “yellow and degrade due to residual acid in the untreated pulp”.
Not a Mimeograph
It’s worth mentioning that mimeographs are not quite the same thing as ditto machines. For one thing, ditto machines were often hand cranked, and many mimeographs were motorized. Interestingly enough, the mimeograph predates the spirit duplicator, having been patented on August 8, 1876 by Thomas Edison and popularized by the A.B. Dick Company in the 1880s.
Also known as stencil duplicators, mimeographs were a competing technology that used ink and stencils to produce 50 to several thousand copies. A special stencil sheet bearing a wax coating would be typed on a regular typewriter with the ribbon disengaged and the machine set to this mode, and/or written or drawn upon using a special stylus and lettering guides.
The stencil sheet would then be fed into the machine, which had a large drum with an ink pad. The mimeograph would then squish ink through the stencil and onto the paper. You can see all this and more in the video below, which illustrates just how much of an art this whole process was compared to makin’ copies today.
Mimeographs were largely done in black, but color could be done “easily”, as the video demonstrates. You basically had to hand paint the colors onto your stencil. It doesn’t seem as though changing out the giant ink pad was an option. Unlike dittoes, mimeographs required better paper, so they should last longer in theory.
Before You Run Off
Duplication for the common man is as important as the printing press itself. While today you might just set the printer to provide the number of copies you need, the history of duplication shows that we’ve come a long way in terms of effort on the user’s end. Keep this in mind the next time you want to go Office Space on it.
“or, if you were loaded” nice one.
That’s not the most memorable scene from Fast Times at Ridgemont High, but ok.
No, they’re not even moving in stereo.
I wonder if the students got their desired Exidy Sorcerer?
In the long, long before Arduino days, I used a few Exidy Sorcerers as embedded controllers (for my company’s high-value projects, obviously, not for personal ones). For a (rather brief) time, they were the most cost-effective solution to get the capabilities we needed. Also, they were very hackable.
I have fond memories of Ditto from grade school. The ones we had were the bluey-purple variety. I remember the smell quite well, and today I recognize it as that of methanol. I never sniffed it to get a buzz, but I did enjoy the scent.
Before now I was unfamiliar with the term “spirit duplicator”. It sounds like the plot twist in a Ghostbusters sequel…
It would have used methylated spirits. Plain methanol is too toxic to handle like that. 10 ml ingested is enough to cause blindness, 15 ml might kill you, and the person doing the copying would have absorbed a significant amount through the skin and by inhaling the vapors.
Methanol is bad for you, but it’s effects are reversed by drinking ethanol. If you consumed about 200 ml of pure C2H5OH (or 500 ml of 40% vodka) then you’d be just fine.
The ethanol doesn’t reverse the effects. The toxic effects of methanol are caused by the liver breaking it down to toxic compounds, but the liver enzymes that break it react with ethanol more readily, which slows down the metabolism of methanol and limits the concentration of the toxic chemicals in your blood. Once the ethanol is consumed, the liver resumes breaking down the methanol again.
Drinking some ethanol merely buys you time to go to the hospital. There they will put you on a drip of diluted ethanol and keep you mildly drunk until the methanol clears out by urine and evaporation through the lungs. They’ll also give you actual antidotes to limit the effects of the toxic compounds that are still produced by the liver while the methanol is there.
Of course, if you keep drinking your vodka little by little for a day or two, that’s the same regime, but you may also need treatment for acidosis and in severe cases you need dialysis to get rid of the byproducts of methanol quickly enough.
Do you have an example of the actual antidotes to limit the effects of the toxic compounds that are still produced by the liver while the methanol is there?
I had (medical) toxicology in my curriculum and never heard of such, but it’s been thirty years. The toxic compounds being formaldehyde and formic acid.
A quick Google search:
“There is no antidote for formaldehyde”, for formic acid it mentions ethanol and fomepizole. Fomepizole just has the same effect as ethanol: it limits formation of formaldehyde.
I’m no expert either, but from what I gather they may inject sodium bicarbonate to control the acidosis.
“Methanol is metabolized to formate. Acidemia leads to protonation of formate to formic acid, which is more likely to penetrate end-organ tissues, such as the retina and brain. In addition, formic acid is more likely to be reabsorbed across the renal tubules from the urine.2 Bicarbonate administration in cases of significant acidemia from methanol intoxication may reverse visual deficits and help decrease the amount of active formic acid formation.”
https://www.amjmed.com/article/S0002-9343(12)00005-8/fulltext
The EPA maximum acceptable exposure limit to pure methanol is 0.5 mg/kg/day which is exceeded by a simple splash of the liquid on the hands. (1 ml = 790 mg) While not instantly dangerous, you’ll start to develop nerve and liver/kidney damage if you keep it up – though you probably wouldn’t want to because it gives you the symptoms of a hangover.
That’s why denatured or methylated spirits only contain up to 10% methanol. The ethanol content actually provides a buffer against the toxic effects of methanol by slowing down its metabolism in the liver, but you still don’t want to mix a drink with it. Just one shot will cause permanent nerve damage and the ethanol is only buying you time to go to the hospital for treatment to minimize it.
In EU denaturated alcohol doesn’t contain methanol because it’s often used as a cheap vodka substitute by students, workers and alcoholics who are not able to afford the real thing. It’s 92% ethanol, 8% water and 0,0001% denatonium benzoate (aka Bitrex) which makes it somewhat bitter, but is non-toxic at such a low concentration.
500mL of real vodka is about 7 EUR while 500mL of denaturated alcohol is 0,90 EUR. Therefore if you can deal with bitterant (vitamin fruit juice helps) then it makes sense to buy denaturat instead of vodka and save money for other things like LEGOs, dev boards or bicycle parts.
There’s many versions. Bitrex is just one. The problems started when people died of methanol poisoning, so they first reduced the methanol to 1% – but then people kept on drinking it – so they started adding isopropanol, Bitrex, MEK, acetone… etc. instead.
Doesn’t help with the smell though. It pushes through your skin and reeks to high heavens.
Also, during the lockdowns, many people realized that hand sanitizer is available just about everywhere, often for free, and contains 70% ethanol with no bitterants added (because it tracks from your fingers to your mouth), so they came up with ways to separate the gelling agent – forcing the manufacturers to start adding 30% isopropanol to keep people from drinking hand sanitizer.
You obviously never licked your lips after using hand sanitizer and inadvertently touching your mouth. What you say might be true for some hand sanitizers in some places, it certainly isn’t an universal truth.
That’s just wrong.
Your math ain’t mathing. 70% ethanol + 30% isopropanol which leaves no room for gelling agents, fragrance, & other additives.
Also high concentrations of alcohol are less effective sanitizers than 65-85% alcohol. Propanol is added for quality control reasons not for effectiveness.
Percentages don’t add up like that. If you have 70% ethanol and 30% whatever, and you add 30% isopropanol to that, you end up with more stuff than you had before. The new mixture will have 54% ethanol, 23% isopropanol and 23% of other stuff.
In practice, the new mixture was 50% ethanol, 20% isopropanol and 30% gelling agent and water. The ratio of isopropanol to ethanol is 29:51 which is to say, roughly 30% of the spirits are now isopropanol.
Yes, they generally taste bad, but the bittering agents are so bitter that even a tiny amount will make everything you touch taste awful. I once had the displeasure to touch denaturated spirits and then stick my hand in a bag of candies – I had to throw them all in the bin.
Sorry, 29:71
it was methanol, at least where I went to school in 1970’s. At that time in the US most of the fruit you bought had been sprayed with lead arsenate insecticide, you could buy sodium cyanide powder at the store for putting in rodent holes etc., and almost no one wore protective equipment. Methanol is still (at least till 2021) as antifreeze in the water filling the underground loop of your new geothermal heat pump loop around here (the smell is something you remember) and still the cheapest thing I guess, the company I worked for (inside parts) used it by the drum….
Methanol solution is used in tractor tires to make them heavier, increasing traction. I have about 400 liters in mine. People are starting to switch to beet juice, of all things. Amazing.
interesting, around here they use a fairly concentrated calcium chloride / water solution for that on tractors for weight/antifreeze. Beet juice? I suppose that would be more dense than methanol solution, maybe sugar is the antifreeze (assuming sugar beets).
I call bs on that unless it’s a 1950s tractor running on tyres with inner tubes.
Tubeless systems used in cars, machines and bicycles require use of special sealant liquid (“milk”) to prevent air leaks. If it’s mixed with water, alcohol or beet juice then it’s effectiveness is pretty much nil and the tyre would go flat in a few days. Check out Park Tool videos on YT and you’ll see what I’m talking about, for example here: https://www.youtube.com/watch?v=-0p5pE4sRJM
Uhhh… No?
Not sure about tubeless bike tires, but I have changed plenty of car tires (as in, actually changed the tire on the rim, not just pulled the whole assembly off and put back on) and there is no sealant required.
I know plenty of guys who run liquid concoctions in their tractor tires for traction. It’s very common.
Fascinating. Beet Juice… heavier than water, not flammable, non-toxic, (don’t want to leak or dump antifreeze where your animals might eat or if you’re using on fields for food production), freezes below -35F, not corrosive to your rims. It doesn’t grow mold because the sugar has been removed. Sold under the brand name “Rim Guard”
I’m still in doubt.
If you’re dealing with methanol vapors and handling methanol with bare hands in an enclosed space, every school day cranking the ditto machine, you will develop methanol poisoning.
Oh, I thought methylated spirits and methanol were one and the same thing? Of course the meths you buy at the supermarket has purple dye added, and something to make it taste terrible so people don’t drink it, but other than that, is there any difference?
It’s in the name – methanol added.
Either the spirits are blended with methanol, or the methanol is not removed in the process of making the spirits. The latter version smells strongly of moonshine, so you can easily tell whether it’s methanol added or just bad booze made out of waste materials and sold for cleaning purposes.
My elementary school had a Ditto machine (and apparently also a copier, that got used less because it cost more). You could tell when the ditto got used because of the purple text.
Fresh dittos were damp and had a smell that I have fond memories of. Maybe because I miss being a kid. Maybe because it destroyed brain cells. Probably both.
We used a Risograph, an automated type of mimeograph machine, up thru around 2010 or so at university. You fed in the master, it would automatically make a stencil and place it on the drum. Select the number of copies and press start—no handling of stencils at all.
We had a photocopier but copies made were about ten times more expensive than the Risograph, so we were supposed to use the photocopier only with five or six copies.
And I recall making a hectograph as a kid. Essentially, a bed of gelatin was prepared in a pan, a prepared stencil pressed onto it and peeled off. Each sheet of paper was in turn pressed and peeled off. I wasn’t able to get a hundred decent copies (note prefix hecto-).
Someone was BSing you.
About half the cost of a photocopy is the paper.
If a risograph was free to run, it’s copies would be half price.
Of course, it’s possible the photocopier was leased from some politicians relative.
Was this in Chicago?
Risographs are still popular for prints and zines.
I thought I read this here before but my memory was off a bit. This was about a similar duplicating device.
https://hackaday.com/2024/01/10/19th-century-copy-machine-the-cyclostyle/#comments
The three sure things in life are death, taxes, and that the photocopier or printer is down again. I’ve given up trying to keep an inkjet or laser printer going at home, and instead, if I need a hi-res print, I send the file to a local Kinko’s or other office-supply store and have them print it. Often the story there is “We’ll do it on this machine over here, because that one there is down.” (If I don’t need such resolution, I’ll print it on my dot-matrix impact printer. Those things just go and go and go, and really the only thing is to replace the ribbon when you decide it’s too light.) But yes, I got through grade school and high school on the alcohol-smelling dittos, and my wife used the ditto machine for her classroom in her early teaching years. My high school had bought a supply of ditto masters that was peacock-blue in color, rather than the usual purple, which made things interesting when I was using a fountain pen with the same color of ink when filling in blanks on the sheets passed out by teachers.
“Isopropyl” should be “isopropyl alcohol” or “isopropanol”. Methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol. Methanol, ethanol, propanol, isopropanol.
Never heard of a Ditto but here in Australia I certainly remember getting purple metho Roneo copies in school.
Class worksheets for my elementary and middle school years were always the classic purple mimeograph copies. I didn’t see regular photocopies until I went to high school (in a slightly wealthier neighborhood). I always wondered how long my old schools kept using those old mimeograph machines (my elementary-middle years were 1990-99).