I created a fully flat white skin to test my meshes and see defects easier. The diffuse is fully white, specular and normal is full gray. However, I see skin details that shouldn't be there, more visible when the skin gets darker.
I'm pretty sure what I see is the default skin specular because I recognize the belly button. It's the same as the default specular replacement I'm using. And when I remove the replacement mod, I see EA's belly button on it.
So, how come my skin doesn't use my custom flat specular?

There are no skin textures in the attached file at all, only a few blank scalps for male child.
Either the wrong file upload, or that's the problem?

I guess I wasn't clear. I want to create a full blank white skin with no texture details at all. But as you see in the screenshot, it's not blank, we see a belly button.

I understand that, but I was thrown by how Skininator names files if they're being reused in many roles- as the files in this .package are named as if they're child scalp textures so it seemed like an incomplete skin. But I see now in the TONE that they're being reused in every slot.
With fresh eyes and that in mind, I'd guess that the culprit is either the muscle cutness or the overlay (which are still using EA textures) or perhaps related to the shared textures. Maybe worth trying making a version just for adult female and including all textures separately as they would appear in a regular skin?

Though when it was brought up in an earlier thread, I was surprised to learn that skins could include custom spec and normals- as a user of default replacers for those, I've never seen any of my sims not utilizing the default replacements regardless of the CC skin. It's possible that this doesn't actually work as intended or lost functionality on a certain patch level.

Not 100% sure, but the size of your textures may be an issue. The game might not recognize them, and use base instead. Try with 1024 x 1024. I guess everything except normals maps can be dxt1.

Ok I tried with all textures at 1024, made it only for Adult Female, added empty overlays, saved without the compact function so all textures were separately in the package, made sure the muscle sliders were at zero. It still shows the default specular. Also checked both in CAS and on-world.

What do you mean by empty overlays? Normals maps are not blank. You can make an "empty" normal by using a gray image, and running that thru the process for making a normals map. Again, I would have to look, but muscle slider ("cuteness" and the cleavage maps) might have a naval, and even at zero, could show. I'll dig deeper tomorrow. Kinda funny, as I made a set of skins similar to what you're doing (black and white), except I wanted the various details.

I'm talking about body overlay textures, not normal map. Overlays show up on everything. That's how the palm stays light when skin gets darker. I added textures with black alpha layers as overlay to make sure what we're seeing is not the default overlay details.
Details of default cutness normal map looks different. This is not it.
As I said before I am sure that the belly button I'm seeing belongs to the default specular. Look closely at my screenshot. That's the exact same belly button from Kurasoberina's Primer skin. When I remove Primer replacement specular files, I see EA's belly button.
I'm attaching the last version of my skin test. (The one I mentioned last time with separate 1024 px textures) - Note that it's only for Adult Female this time, not Young Adult.

Skins also use an actual Overlay texture, which I pointed out in my second reply. I think EA's just makes the palms of sims' hands pale, but it was worth testing without to rule out EA textures interfering.


I had a little bit of a Eureka moment about this, though.
Don't all clothes include a skin specular? Specifically, all of EA's CAS parts point to the texture key for the default specular. CC clothes, depending on how they were cloned, may point to the same one or have their own copy in their package.
I don't think there is a feasible way for a skin to have its own specular, with that in mind. You may just want to include a blank replacer for the default.

Wow, never would have thought of that. So custom skin speculars ARE useless afterall. Thanks a bunch, I'll just make a flat replacement for it then.

Yes... yes they do, and that is a very real possibility.