I am working on a laminated gunstock for a rifle. The laminate is called yellow jacket. It is yellow and black. The black part has a few brown places in it where apparently the black stain did not take. I considered using a black marker pen on it or a #2 pencil before applying a finish. Has anyone ever encountered this and what did you do? I am afraid the marker pen might be too dark as the black is not jet black, just black shaded.