In maya I was able to make an impressive roughness for a character using procedural noise to control the roughness of the face. Basically black colored areas on the uvs had less procedural noise and white had a ton of noise. The black areas are shiny and the white areas are diffuse and the affect is very realistic combined with a displacement map for the face details.
Can uv image be hooked up to control the strength attribute of the bump vector shader (may switch to displacement for final renders). Id like for the lips to not have any noise to be shinier. Its more physically accurate. The arrow points to the node that would control what I want. Not sure what nodes I’d have to add.
On second thought it actually does matter how you place them, even though depending on the use case both variants might be useful.
However, for this case you probably want to go:
image texture → multiply → add
That way the “multiply” allways determines the raw range of the the brightness and the “add” always determines the raw offset.