How do you stop paint from pooling in the deep wrinkles on head sculpts?

The pooling into smile lines and eye sockets is kind of the nature of the beast when you wash a face, but there are ways to keep it from going dirty. First thing: washes look blotchy on resin when the primer coat is too smooth or too thick, so I switched to a matte varnish pass over the primer before washing. Matte gives the wash something to bite into and it dries in an even film instead of breaking apart. Second, I stopped applying washes straight over bare primer on faces entirely. I lay down the base skin tone first, let it cure, then wash. The wash glides over painted surfaces way more predictably than over raw primer, and it stains less, which is where most of the dirty look comes from. A wash is supposed to tint, not stain. If it's staining, it's too thin or sitting too long. I pull the excess out of the deep lines with a brush dampened in thinner after about thirty seconds, wicking toward the lines but leaving just a whisper in them. That's what keeps them looking shaded instead of grimy. And at small scale, less is more. A wash that looks subtle wet will read strong once dry.

Gotta push back on the idea that staining is the problem. On skin, a wash that stains is exactly what you want, that's how you get gradual transitions instead of hard edges around the nose and brow. When faces go dirty for me it's almost always a pigment-heavy wash sitting on top instead of soaking in. I switched to glazing with paint thinned way past wash consistency, working one small zone at a time while it's wet. Stains the base tone, no pooling to fight. Also curious what thinner you're using, because the wicking trick behaves totally different with alcohol vs water on my end.

On the scalp lines, I stopped trying to sand them and just flood the top with a couple mist coats instead. I hold the airbrush back and build up thin layers, letting each one tack off before the next, and the lines soften up enough that paint hides them. The detail on top of the head is usally smoother than the face anyway so you can get away with a heavier build there. I did try a runny filler once on a bald sculpt and it pooled in the same spots like a wash does, so I quit that fast. Curious what scale you're at, mine are around 35mm heads and at that size the lines mostly vanish under the base coat.

I do mostly fantasy busts so my skin tones are greens and purples, but the pooling thing happens to me too. What helped was switching to oil paint for the shading. It stays wet way longer so I have time to fix anything that gathers weird before it dries blotchy. Also curious if anyone else does this, do you folks thin your acrylic wash with water or with proper thinner? I only ask because mine behaved completely different once I stopped using water, might be part of the dirty look.

Beginner here so take this with a grain of salt, but I noticed my test heads behaved way better once I let them sit under the UV lamp a bit longer before priming. When I rushed that step the shading paint woud go on wierd and patchy in places, kind of like what you're describing. Also I practice on cheap white doll heads from a craft store so I'm not wasting prints while I learn. Does the resin color matter at all for how the shading paint sits on top?

Update: tried the oil paint tip for shading and it's a big improvement. Having that open time means I can wipe the pooling out of the smile lines before it dries dirty. Still fighting the scalp though. Tried the mist coat thing with a couple thin passes but the lines still ghost through. Do you keep building coats til they vanish, or does the primer color matter for hiding them?