I haven't found the exact mix of colors to be all that critical. I drop of Selenium Brown and 1 drop of Neutral works fine for me with both my former paper of choice, Forte Polywarmtone, and my present paper, neutral tone Foma FB VC, both toned in 1:20 KRST. FWIS I discard any prints with really large white spots (which I seldom have) but have good results with small dust spots. The key, for me, is a really good brush from an art supply store.