Don't ask where I get my formulas. I am an absent-minded professor.
I collect formulas and try them as I get time, but I am also of the
"if it ain't broke don't fix it school" so if I find something that
works I leave it alone until someone shows me something better.
Third ingredient is my old friend Oxalic Acid, which if you remember
I also use in my cyanotype formula because I believe it gives me whiter
whites and less bleeding. That one I have tested but not the Kallitype
formula variations. For the record:
Oxalic Acid 0.5 gm
Ferric Oxalater 7.8 gm
Silver Nitrate 3.1 gm
Water 47 cc
Allow to "ripen" for three days before use.
Since the metric quantities are somewhat strange I suspect that this
was an "old" formula that I converted from an English system
Bob