Unfortunately there aren't common substances with those potential color developers, one of the only ones are some hair dyes containing PPD. Some people have already tried it, but only a few had some success. I have been trying this for a long time but I couldn't realy get an acceptable result, until today. I also tried para-aminophenol, aka paracetamol, reported also as a weak color developer with tenuous results.
Then I prepared a «soup» containing hair dye and developed the piece of film for 1 hour at more or less 37ºC (100ºF) in my kitchen sink. OK, not only a time, it was the third attempt. I first used 15 min. at room temperature, then 30 minutes at room temperature and finally full one hour at 37ºC.
And my recipe was this one:
50 ml hair dye containing PPD
0,05 g phenidone
1 g sodium sulfite
5 g sodium hydroxide
10 g sodium bicarbonate
5 g potassium bromide
Water to make 500ml
The film looked like a B&W one but at scanning I saturated the colors and also with software afterwoods.
The film I used was a movie film, Fujicolor Eterna 250D, and I first soaked for 30 minutes in just Soda to remove the remjet and then washed and developed. I then fixed to see the silver image but the film was already transparent like bleached. But I used then a Blix bath to be sure that only dyes are on film.
Note: The only special stuff I used was Phenidone like suggested here, and I still don't know if it goes without it. I will try it later because it is important that the developer is realy made from scratch.
Update: I did another modification, without phenidone and without Potassium Bromide. Yes, it works too, I will be publishing the results very soon. So, the recipe is now as follows:
50ml hair dye containing PPD
5g Sodium Hydroxide
10g Sodium Bicarbonate
2g Potassium Metabisulfite
Water to make 500ml
I first dissolved the hair dye in some 100 ml water and Sodium Hydroxide also in some 100 ml warm water. I mixed both and stir a lot and let it react for 3 hours. I did this because hair dye is oily and reacting with Sodium Hydroxide will change a part of it to soap. During this three hours I stired sometimes too. But maybe the PPD also reacts with Sodium Hydroxide, I don't know. Then, after three hours I added Sodium Bicarbonate that will also react with Sodium Hydroxide giving Sodium Carbonate. This will lower pH a lot. Finally I added water to make 500 ml and Metabisulfite as preservative.
It works much faster, I only needed 20 minutes to develop. I think this is because it has no Potassium Bromide which is a restrainer. But I couldn't see differences until now. Maybe with KBr you get sharper images but this is not a problem for who just want to use common substances and KBr is, somehow special. Maybe salt, Sodium Chloride may be used instead.