|Thomas Moran, Cliffs of the Green River, Amon Carter Museum, Fort Worth Texas|
For me it's important to look closely at the surfaces to see the hand of the artist. For instance, here are three closeups of the Moran painting. With the top photo I'm interested in his trees and the edges of the hill and sky.
Beautiful clouds here and nice darks. The warmth and dark values in the foreground are interesting to see.
But this closeup is what I'd wanted to really nail: the reflections in the water in the lower left of the painting. Thinly painted; very nice.