So weird, the erroneous information that continues to continue to be put forth on these forums. I would bet that those who say that Amidol has a short tray life have never used it. Or if they used it, used a bad formula. When I mix up Amidol it lasts all day--up to 12 hours--and I have even used it the following morning after having it sit in an open tray all night.
Yes, there are many Amidol formulas. Most are worthless for modern paper.
Amidol will work just fine with Benzotriazole. It is the choice for those who want cold-tone prints rather than warm tone prints. As for the amount to use, you will have to experiment. I last did it so long ago that I have forgotten how much I used of a 1% solution.
Amidol does not stain everything. I think that myth started when, as Jim mentioned, the Chinese Amidol appeared. That Amidol does stain everything.
When we originally tested the Chinese Amidol it was like the English Amidol. We recommended that the purchaser go to China and test the actual Amidol he was buying. We even arranged for a darkroom there. Sadly, that did not happen. The Chinese switched out the finer Amidol we had tested and gave him the impure stuff. It works, gives great black tones, but it does stain.
Michael A. Smith