Odilon Redon " "My drawings inspire, and are not to be defined. They place us, as does music, in the ambiguous realm of the undetermined"

Odilon Redon is beyond explanation, he was his work. He was a natural and exquisite colorist, I do not think you can learn color, unlike drawing, it is inborn. His work was either brilliant and full of color or noir as he liked to call it. He worked in oils, gouache and his pastels were incomparable.

I found that ARTSY has a very good collection of examples in high resolution that you can study.

https://www.artsy.net/artist/odilon-redon

Evocation, undated, private collection pastel

Violet Heyman Cleveland Museum of Art Pastel

Japonaise vase with Japanese Warrior
Foundation Beyler pastel

Fleurs Fleurs Foundation Beyler oil

The Smilng Spider MOMA

charcoal