Gary;
There are several environmentally friendly sets of chemistry out there, but you will never see one that is drinkable just due to the laws of chemistry and physics and human physiology.
As for a dye, yes there is a test kit. It turns yellow when the print is not washed properly, but the dot is permanent. I test on the borders of my prints. Again, using a true dye and washing it out of a print involves potential staining of the print. Maybe, but no guarantee, especially since the existing test is so simple and cheap.
PE
I was exaggerating about the "drinking" part, and I've used the Silvergrain products, which are supposed to be fairly eco-friendly. I've also used some toxic stuff, which I bottle up and take to the hazardous waste dump. I haven't tried the Liquidol, but I just read the data sheet, and I'm intrigued. I've used Photographer's Formulary stuff extensively, so I'll get some on my next order.
I've also used the Photographer's Formulary test kit, but it always spreads out into the image, seemingly no matter how small of a drop I put onto the boarder. Perhaps "dye" was the wrong word to use. I'm nowhere near being a chemist, but if something could be developed to give the residual fixer a slight color that would wash away completely when the print becomes archival in the wash, it would be a great help.
By the way, Last time I used my residual hypo test, I noticed that it was out of date by a couple months. I got no visible spot on the print, so I initially thought that the wash had been finished after a remarkably short wash. Will the test kit lose its effectiveness once ot is out of date? A further piece of info. I had just switched from Orbit Bath to Heico Perma wash. I was using Forte Polywarmtone FB (my last box).
