Trying to copy a couple of Marins.
Difficult but engrossing.
Learned a couple of things:
He uses a lot of black-- or at least that's what I used to approximate the colors on my reproductions: both grayed and full strength. Or mixed with colors, esp. greens
He uses shorthand marks: squiggles and upside down Vs for trees; small slashes for grasses.
He doesn't mind outlining.
My colors lack the subtlety of his (my copies are about half the size of his, and done quickly). And I'm not too good with the charcoal.
But I did feel like it helped me gain some insight into Marin's practice.