I found the formula, but I had remembered it wrong... it was for
"brilliant blue" on blue-toned silver prints: 25g salt in 1 litre wash
water. I'm dubious about it, since blue-toned silver prints are brilliant
blue to begin with, but I guess it's worth trying....
Meanwhile, everyone does know that you can make a dandy silver print blue
toner out of your A& B solution for cyanotype, right? (Exactly what you
pay Berg and Brown $10 for.) 10cc A and 10 cc B in 10 to 16 oz water, with
72 cc 28% acetic acid. (Sorry to mix avoirdupois and metric , that's just
the kind of person I am.)
Judy