What method do you use on those sheets to get the colour discrepancy? Is that a blending mode layer afterward or some kind of process while painting?
it’s actually pretty simple (and I’m glad you noticed, makes a difference doesn’t it?)
I do these while I’m painting, after I’ve established the base colors and simple shading. Mostly because I want to be able to sample these colors a lot while I’m rendering, it really comes in handy.
On a new layer, with color blending mode, I take any large scatter brush, turn on color dynamics, and push Hue Jitter to 100%
Then I choose a color that is decently saturated, and go to town brushing everywhere.
Then I just turn down the opacity until it looks right.
Of course that’s not all. I’m also using a layer above on Soft Light blending mode. I use this for stains and streaks.
No special brush for this, just one that has a texture to it and is useful for painting streaks. I’ll color select from the area I want to paint over, so it makes it a little darker and alters the color only a little. Then I lower the opacity a little, and we’re set.