Real Pigment - a skin tint fix

(Please make sure to read the installation and compatibility instructions below!)

This mod will apply to all heads (both PC and NPC), making the skin tints apply to the face and scalp in a way that looks more like how pigment can be distributed in the skin. There are three options, and there are also files available to apply the different tint maps individually to different characters if you wish. The tint map and makeup maps are unavoidably contained in the same file, so smooth makeup is included (more below on the available compatibility files and replacing the makeup if you wish).

Note: The headmorphs in the screenshots are not part of this mod; they're just there to help showcase it!

As always, if you enjoy this mod and want to upload screenshots for it, that would be great! I would also be delighted if you want to improve on it; there is a PSD available in the Miscellaneous Files section if you wish to do so.

About

What do skin tints have to do with the makeup file?

The alpha channel of the makeup file (uh_hed_maka_0t), previously acknowledged as the source of the "patchy skin" issue (where the darker skin tones appear blotchy), has nothing specifically to do with the makeup in the red/green/blue channels and is actually the face tint map.

Why vanilla and vanilla-based fixes don't work

The short version

The base face textures are pale and are darkened by the skin tints. Tint maps work by applying more tint in light areas on the map, and less in dark areas. The vanilla tint map is also based on a face texture, which means it includes shading: this means that less tint is applied in the shadows and more in the highlights, producing an inverted lighting effect that counteracts the actual lighting and makes the face look flat. I also don't think it lines up with how pigment tends to be distributed in faces in real life.

This means that replacing the vanilla map with one that still has the same kind of shading -- even if higher quality -- will still result in the same problems.

The long version

(To reiterate: tint maps work by applying more tint in light areas on the map, and less in dark areas.)

So, for starters, the vanilla alpha channel has speckles that produce a "patchy" appearance; I think everyone can agree that that was a poor choice, and this is what SJC's groundbreaking Patchy Skin Fix concentrates on by using a much smoother image.

But it's not just the speckles. The vanilla alpha channel contains a lighter, flatter version of one of the face complexions (plus those speckles), meaning that the light and dark areas roughly correspond to the light and dark areas on the complexions, whether due to colours or shading -- for example da