How do you add surface imperfections?

[Harris_Majeed]

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.

[lee_griggs]

Are you using the scratches osl shader? If so, there is an example at the bottom here.

Otherwise, it's output -> specular_roughness

[Harris_Majeed]

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.

[lee_griggs]

You can connect the file texture to a range or color_correct shader to control the results in the specular_roughness.

[lee_griggs]

Can you share some images of what you are getting vs what you want? Here is a working example of a roughness map (MtoA).

[lee_griggs]

Did you try the scratches osl shader?