How do you add surface imperfections like smudges or scratches onto a standard_surface? In my case, I'm trying to add scratches to a shiny metal surface.
If I do that, the metal will not have many specular highlights and won't look shiny. How do I preserve the roughness value so that the metal is shiny while also adding scratches using an image? I would not want to use a separate gloss map.
Can you share some images of what you are getting vs what you want? Here is a working example of a roughness map (MtoA).
Did you try the scratches osl shader?