From a Van Gogh letter

Vincent van Gogh to his brother Theo, November 16, 1883:

The ride into the village was beautiful. Enormous mossy roofs of houses, stables, covered sheepfolds, barns. The very broad-fronted houses here are set among oaktrees of a superb bronze. Tones in the moss of gold-green, in the ground of reddish or bluish or yellowish dark lilac-greys, tones of inexpressible purity in the green of the little cornfields, tones of black in the wet tree trunks, standing out against the golden rain of swirling, teeming autumn leaves, which hang in loose clumps — as if they had been blown there, loose and with the light filtering through them — from the poplars, the birches, the limes and the apple trees.

The sky smooth and bright, shining, not white but a barely detectable lilac, white vibrant with red, blue and yellow, reflecting everything and felt everywhere above one, hazy and merging with the thin mist below, fusing everything in a gamut of delicate greys.

The Letters of Vincent van Gogh , ed. Ronald de Leeuw, trans. Arnold Pomerans (New York: Penguin, 1997).

Also from Van Gogh’s letters
“Admire as much as you can”
“It was a bright autumn day and a beautiful walk”
“Lately, during the dark days before Christmas”
“So you must picture me sitting at my attic window”
“At the moment, I can see a splendid effect”