Quote Originally Posted by nworth View Post
If fixed out photographic film works as a tissue base, cheap inkjet transparency film (used to make overhead projector slides) probably would too. One side of that material has a thin gelatin coat to accept the ink. A possible problem is thickness. Inkjet film is thinner that sheet film, and it will probably curl more. I've heard that ordinary artist's mylar (available in rolls quite cheaply) also works. I haven't tried any of these.
Sheet film is thicker than one needs. The litho film I use is about half the thickness of sheet film (.004" vs .007"). The test is to put the support material in hot water to see if it deforms or falls apart (it should do neither).

If one brush sensitizes, 100 grams of Ammonium dichromate will last a while. For tissues to print 8x10 negatives, one might be using only 0.1 to 0.6 grams per tissue...depending on the concentration used (lower concentrations will yield prints with more contrast).