@mayasky, those colors were shown to me by mine professor of grafik art. She is using them to make some moments very like copper etching effects
https://www.google.rs/search?rlz=1C1GGRV_enRS751RS751&biw=1366&bih=675&tbm=isch&sa=1&ei=MMfdWrP2FYeWkwXwv4rYBQ&q=ljiljana+stojanovic+grafike&oq=ljiljana+stojanovic+grafike&gs_l=psy-ab.3..0i24k1.10504.14482.0.15060.19.14.0.5.5.0.125.1041.12j1.13.0....0...1c.1.64.psy-ab..1.8.313...0i30k1.0.8mN4KSBSnRE#imgrc=0Ub-t0FZRmYpzM:
Maybe you can see her influence :)
Try them, great colors for playing.
Ah, yes I can! :) Great etchings too! :) Thank you for showing me, I will definitly try them out :)