How to add imperfections to materials? For Diffuse and Reflection Map

[Ben278]

Hi everybody. In my case, I want to add some imperfections/dirt to a plaster material (exterior wall). It just looks too perfect and also the reflection is to even? What would be the “best” way to do this?
Using composite Layers in the diffuse slot or working with the reflection color or the reflection glossiness? And what map typ is good to add some variations to the reflections? Thanks for the help.

[romullus]

It's better to leave reflection colour as pure white and map diffuse and reflection glossiness instead. Any compositing node will fit here - mix, Corona mix, composite, mask. Use whatever works better for the situation, there's no hard rules here.

[Ben278]

Thanks for the help. But should the reflection color always be untouched? I just wonder, because you can see it beeing used in some tutorials or youtube videos.

[romullus]

For dielectrics reflection should almost always be pure white. On the other hand most metals has coloured reflection. I suggest to watch some official Corona YT channel tutorials to get basic ideas about materials.