Is there a way to place a material over other materials (subdermal base)

Question

i was investigating on how to properly make a realistic skin and i found that to make one i need to combine the skin texture (skin texture and imperfections) + a subdermal base (veins and such) + the subsurface scattering.

So, i was thinking: "Mmmm, okay, let's just use two image textures with a Mix RGB and and change the display to "Screen" or "Multiply" and both will be seen in my skin texture"

But i found that the results are not very "convincent" (maybe i'm doing it wrong), so... there's an alternative or "correct" way to do this?

The thing is that i want to make something like this:

Use a Subdermal Base with the veins and muscle red colours

The skin texture over the subdermal base which will give the skin a realistic look

Answer 1

Try using the Principled shader. It has SSS, diffuse, and roughness all built in. Connect the subdermal texture to the SSS color input, the skin texture to the color input, and set the SSS amount to something other than 0. You will probably have to adjust the subsurface radius to get it looking right. If I recall correctly, you want the red value (the top one) to be the highest by a fair bit, then green, with blue slightly below green. The radius is essentially the 'depth' of the scattering effect for each light color (RGB). Human skin is red when you shine a light through it, so that is why you will want the red value to be higher. I believe the radius is in blender units, so keep that in mind with the scale of your object. You don't want the radius to be larger than the width of your model, as that will make the entire hand translucent, and look fake.

Some other things to consider to get great looking skin is some subtle bump and a roughness texture (using the Principled roughness and normal). That will really help make the skin look realistic, as skin has some subtle reflections and surface texture.