As far as i understand, thousands of substances, given the apropriate time, will be able to produce an image on film. I am trying to compile a list of weird (not conventional) developers that will produce an ACCEPTABLE film development at acceptable development times. So far i came up with:
CAFFENOL
PARODINAL (not conventional because you start with a medication instead of a pure chemical)
The formula for PaRodinal originates from Sreenath,it can be improved by using capsules where the contents can be tipped out and by reducing the amount of sodium sulfite,this gives a clear solution with less crystals. www.photo.net/black-and-white-photo-film-processing-forum/00UxmB
If you can do the calculations and take safety precautions it is possible to make developers in which metol is replaced by p-aminophenol made by the reaction of paracetamol (tylenol) with sodium hydroxide.I have made a D-76d copy ,adding sodium sulfite and pharmacy boric acid to sodium aminophenolate solution.It takes about twice as long to develop a film as does D-76d but the grain is similarly fine.By this means a copy of any metol formula can be made in which the metol is replaced by p-aminophenol.
Unfortunately the amateur cannot make metol or phenidone.
I have also made a developer using all the developer cream (the sachet marked as containing p-phenylenediamine) from 4 packs of black hair dye dissolved in 1L water,with filtering and addition of alkali.There is a health concern about p-phenylenediamine though.
There's the somewhat-well-known account of a patient with a disorder called alkaptonuria: http://www.cmaj.ca/cgi/content/full/172/8/1002. The paper doesn't mention the development time, though.
Grant Haist devotes a portion of a chapter in his book to this subject. It is my suggested reading item for anyone attempting to do this type of compilation.
There's the somewhat-well-known account of a patient with a disorder called alkaptonuria: http://www.cmaj.ca/cgi/content/full/172/8/1002. The paper doesn't mention the development time, though.
Ferrous sulfate in the presence of oxalate ion produces a neutral black image with very little fog. It does not fully develop the latent image so there is a speed loss. However this is not a problem for papers.
Vanadium ions were used in commercial processing of positive films. The action of used developer can be restored by electolysis. One thousand meters of 35 mm film can be developed in only 1 liter of developer.
Uric acid is a weak developing agent.
A powerful developing agent glucic acid (reductone) can be made from glucose reacted with sodium carbonate.
Vanadium ions were used in commercial processing of positive films. The action of used developer can be restored by electolysis. One thousand meters of 35 mm film can be developed in only 1 liter of developer.
Interestingly enough, skimming that article, I knew several of the authors there personally. I can say that nothing ever came of the Vanadium developers as evidenced by later publications.