so I am thinking about how the one thing that real oils and to a lesser degree acrylic paints that digital painting can't. A glaze adds so much to a painting. It give a work of art a translucency that almost looks like real skin. Then it hit me. Hows about trying a glaze in the digital world? But how Tommy? Well do your painting as normal then pick a spot or two that would normally get a glaze in real life, say the cheeks. You know how they have a red tint or around the eyes where it's blue. Well add a new layer and grad the air brush? I think it would work the best for the glaze. On this second layer or what ever layer as long as it's the top one glaze it up. now instead of printing as is print the bottom layer on a matte finish paper and for the top layer print it out on a transparency sheet and throw it over the top of the matte of coarse. viola a glazed painting....digitally. well I haven't put this to the test because I just thought of it today. please give it a try!! I will soon.
I glaze constantly in photoshop. I use a lot of layers set to color, overlay, soft light or other blending modes to tone and tint certain areas. It keeps areas from getting flat and boring, and you can bring in a ton of color and keep it keyed to the right value to really make areas come alive. Good luck with your experiments, I highly recommend this for great effect and to tie paintings together.