I use one brush - one for blue pigments, one for red pigments and one for yellow pigments. I dont use a smoothing Brush but might try that on my next Gum print
One different brush for each color and no smoothing brush. I have tried foam brushes but they didn't worked for me. I have tried an airbrush but with no conclusive results. Maybe a better airbrush would work. I am curious, has anybody else tried airbrushes? And with what results?