Pure drawing is an abstraction. Drawing and colour are not distinct, everything in nature is coloured.

[T]reat Nature by the sphere, the cylinder and the cone. . . .

Shadow is a colour as light is, but less brilliant; light and shadow are only the relation of two tones.

Drawing makes you look at the world more closely. It helps you to see what you're looking at more clearly. Did you know that?"
I said nothing.
"What colour's a blackbird?" she said.
"Black"
"Typical!

For an impressionist to paint from nature is not to paint the subject, but to realize sensations

Painting from nature is not copying the object; it is realizing one's sensations.