Help understanding roughness

[zooropa]

HI. I decided to give it a try to Luxcore after a couple of years.
I am a bit confused about a scene I am building:



I am adding roughness maps to create a bit of imperfection, but I can not manage to notice anything in the render.



It might be the lighting, and maybe I should choose a different hdri with more contrast I am also not sure I am mixing the roughness maps correctly.
I tried to rotate the hdri and even when I picked the contrast area, I could still not see many details of the roughness.

I would like to share the scene but all the textures are paid. I am not sure if its possible without getting into legal issues.

Hope you can help me

[Sharlybg]

Your Hdri is to dull and flat to see reflection properlly.

[zooropa]

Thank you, I have been following your videos on materials. I was wondering. Why do you set your roughness to 2.2 in gamma? shouldn't it be 1?

I was also wondering how you tweak your maps; for example, there is a map range node in cycles. Should I use the color ramp to adjust my scratch intensity?

[Sharlybg]

You are right map gamma should be set to 1 for all non color maps.
sometime one can let it at 2.2 or higher just to make it more contrasty.
But it is better to use the color ramp node of luxcore for that.