It is confusing. A lot of this stuff with TEA (triethanolamine) and PG (propylene glycol) are being made up as we go along - they've never really been published as formulas. Go to and read Patrick Gainer's articles and Sandy King's articles. Sandy created Pyrocat-HD developer.

As for some of the others, MS Amidol is Michael A. Smith's version of the Amidol print developer - go to his site - you will be reading quite a while.

PPPD is a pyro based print developer compounded by Don Miller and first (I believe) published on this site.

I'm exhausted. Someone else take over.