Hi! I’ve been using Quick Sketch for creating creature concepts. Is there a way I could selectively mask the dark color in the attached quick sketch. I will then invert the mask to paint inside the dark area. i tried various masking options ( mask by, hue, intensity, saturation, alpha ) but the only parts that do get masked are the blue areas. Any suggestions? 
Use Zapplink to quickly bring it into photoshop, create a selection for the mask (Save Selection name it Stencil. If you’re unsure of that workflow search here: http://www.pixologic.com/docs/index.php/ZApp_Link).
Then bounce back to zbrush and you’ll have a mask ready to go in the Stencil palette. Just bring it up by hitting enter.
Thanks so much for the technique. Works like a charm. There was one problem i ran into but i resolved it. With QuickSketch the default shader is the flat color shader and for some reason ,with this shader active, painting done in PS when brought into ZBrush through Zapplink doesn’t get picked up. So i changed the shader to basic shader before sending the Quick Sketch into PS.
