Haven’t seen this posted yet, came across it while researching PBR in UE4, should be helpful for artists reading up on PBR:
This graphic chart was made for the artists to help them with the physically based rendering (PBR) workflow present in the Unreal engine 4.
That looks good, I’m wondering though, are those colour values based off of real-world examples or just what the artist thought looked good?
Trying to figure that out myself
This was already posted here: https://forums.unrealengine.com/showthread.php?2922-Sebastien-Legarde-s-material-reference!&highlight=Chart 
