Im using blender to create jewellery, as you know jewellery is finished with a high polish so that the surfaces are almost mirror like, this is easy in blender but in the jewellery trade nothing is quite perfect, every surface has very slight imperfections and things this is how you separate a render from an actual ring, is there a way to recreate this? I have not yet found any normal maps with the right imperfections or any other method that recreates such a subtle yet important change to the mesh? All ideas welcomed.
You could sculpt a high-poly version and bake the normals, but I guess the easiest way to do it is to fake with a procedural texture. Here is a chain of nodes that works in my opinion: Texture Coordinate (Object output) > Mapping > Vector input of a Noise Texture > Height input of a Bump > Normal input of a Glossy > Material Output. Note that you can play with the Noise Texture node parameters to make the defaults bigger or smaller:
Also, if you want some more or less glossy surface parts, you can plug a Noise Texture node into the factor of a Mix Shader so that it separates 2 different Glossy shaders.