We still use a "Turkish Delight" duplicator for small print run stuff (apa contribs, small con newsletters of the informal persuasion) and security printing (Postscript output -> ghostscript -> 9 pin printer -> coloured Banda paper --> unduplicatable tickets for whisky tastings etc).
Anyway, here's Jenny's recipe (as obtained from a friend of a friend of a 'freedom fighter' who apparently used to run across the veldt duplicating leaflets with one hand and scattering them with another ...)
[This recipe uses gelatin, which can be produced from non-animal sources, but which usually isn't. Somewhere we have an equivalent recipe that uses carrageenin gel or agar agar, but you will have to work these ones out for yourself by trial and error, as we're not so practised with these ones]In a large saucepan dissolve 100g gelatin in 375ml water then begin to warm it gently while adding 385g of sugar. When it has dissolved, add 715g glycerol and slowly bring the mixture to the boil. Stir gently for one minute while boiling to avert the wrath of the Foam Ghods.
Remove the mixture from the heat and pour it slowly into your tray (care! this mixture boils at a higher temperature than water -- for the purposes of rug rats and house apes, treat it as molten fat).
Make sure that the tray is on a flat surface where it can be left for a few hours until the gel sets.
While the gel is cooling, the Foam Ghods can be further appeased by using tissue paper to remove bubbles, foam and 'bits' from the surface.
Take your master copy and lay it face down on the gel, smoothing it down with the back of a spoon (or by hand), taking care to avoid bubbles and areas that are not in contact with the surface.
Leave it there for a few minutes to allow the ink to transfer into the top of the gelatin (care: the longer you leave it, the deeper the ink goes, so the more copies you can make, but if the surface was too wet, you run the risk of incurring the wrath of the Dhemons of Diffusion).
Remove the master carefully (it may be re-usable, depending on how many copies you need) -- if it tears, never mind, the surface was too dry anyway.
Take a sheet of ordinary paper and slowly smooth it down over the right part of the bed. Peel it back, and step back in amazement! It works!!
Repeat 30-50 times, omitting the step back in amazement as the miracle becomes mundane. If you want more copies clean the surface (see below) and replace the master.
For serious damage, remove the gel from the tray, and redissolve in a little boiling water, bring back to boil as above and continue with the procedure as appropriate.