Even van Gogh was searching for good colors and good art supplies. Here is an excerpt from Dear Theo - van Gogh's collection of letters to his brother, benefactor and confidant:
My dear Theo,
...If you want to do me a great favor, send me by post some pieces of craie de montagne - a kind of crayon/pastel. That crayon has soul and life - I find Conte crayon lugubrious. It's as if 2 violins had more or less the same appearance, but when you play them one produces a fine tone, while the other is useless.
That crayon has a lot of resonance and tone. I'm tempted to say that it understands what I want it to do that it understands what I want it to do, that it listens intelligently and obeys, while Conte crayon is apathetic and unwilling. Craie de montagne has the true soul of a gypsy; send me some of this marvelous stuff, it it isn't asking too much...
(From the book, Colors, the Story of Dyes and Pigments by Francois Delamare and Bernard Guineau.)