This morning I got into the studio with a thought: layering pigments.
Each color pigment has it's own opacity, some more than others. With the sketch card process of rubbing or painting the pigment into porous papers, I realized that those more translucent colors could work out to be a sort of glaze. Some colors being of higher quality could also be manipulated into effective deepening or darkening of the chroma by simply adding more pigment to an area. The idea is simple I'm sure to the more learned, but at this point I've only been painting for a few months and these particular concepts and techniques aren't known to me.
This particular card's design works for me. I'm more illustrating (which I'm not terribly interested in) than anything but in reducing my mode of work I could concentrate on the simple task of learning how pigments can be manipulated for depth rather than simply color hues. Within that, I could set aside the more emotionally artistic process and just let the pleasing lines of illustration do their work.