>>96358777
I mean if you want to be really fancy you can use the contrast medium to thin contrast paints, I just find they come out of the airbrush looking better if they're slightly watered down. I just use tap water.

If the red basecoat seen in the kroot skin is not appealing for your orks I'd probably go for purple instead.

But yeah in short the light white/cream zenithal over red/purple/blue base with an airbrushing of some contrast is the way to do skin for mass infrantry armies. Imo doing any more beyond that usually ends up looking bad and is just self torture. Once you do the guns and armor on top of that skin starting point, the models will look good. Again, picrel.