Jochen...Well I do have a verbose colour library(from the Dare to Imagine book from my Imagine3D days) with the R,G,B, values for reference but for some reason when I try for all my other senses, nothing works out. When I used to paint it would be a matter of do overs so many times I'd wind up with a ton of acryllic on the board and no results..I think for me it's a disruption in the tonality tween similar colours that messes me up..tried a PF grass colouring and it looked awful, not just my opinion as my neighbour came by to check it out and said it lloked like puke but seemed O K to me. He tweaked the colours for a short while and it did look better but I can't say how it was different....sigh