When I paint papers to use in Mixed Media collage, I use many tools and gadgets to create interesting textures and surfaces for my painted papers. A fun way to work is to apply paint with a painters putty knife of a palette knife. I have a very durable painter's knife that I picked up at a tag sale which has become one of my favorite tools. It is much stronger than some of the products out today, Try experimenting with applying one color at a time to your papers or see what happens when the putty knife picks up several colors in the process. After the painted papers dry, I am ready to tear them up and use in my next abstract collage.