I am trying to figure out how to bleach a small area of a print. There is an area of clouds in one of my prints that just seems too dark and out of place. I have some potassium ferricyanide salt from the Photographer's Formulary cyanotype kit. I could mix that up. But then I need to figure out what strength to use. At that point, as I understand it, I could paint it lightly on the area in question after it is fixed, right? I also have the liquid cyanotype kit with solutions A and B -- is one of those potassium ferricyanide?