Wow! Those are amazing... a real understanding of classic pulp color pallet.

Looks like some sort of simplifier like buzzpro is used possibly in some (or else some thing like paint daub or even just facet on separate color channels) then lots of painting with the smudge tool... maybe a posterization with a pulp color pallet? Desaturated and hand colored with that pallet?

Doesn't look like a hue shift but an actual conversion to that old low key pallet. Any one have ideas what is going on? Anyone extracted a color pallet from that old art and figured out how to get it in an image?