How the Impressionists changed the colors we use to paint shadows.
Once you start painting and closely looking at colors, you soon realize that simply reaching for a tube of black paint whenever you need to put in a shadow doesn’t work. The result isn’t subtle enough to capture a realistic shadow. The Impressionist Renoir is quoted as saying “No shadow is black. It always has a color. Nature knows only colors … white and black are not colors.” So if black was to be banished from their palettes, what did the Impressionists use for shadows?

The True Colors of Shadows
Working from the then-relatively new theory of complementary colors, the logical color to use was violet, being the complementary of yellow, the color of sunlight. Monet said: “Color owes its brightness to force of contrast rather than to its inherent qualities … primary colors look brightest when they are brought into contrast with their complementaries.” The Impressionists created violet by glazing cobalt blue or ultramarine with red, or by using new cobalt and manganese violet pigments that had become available to artists

Monet painted his moody interiors of Saint-Lazare station, where the steam trains and glass roof created dramatic highlights and shadows, without earth pigments. He created his astoundingly rich array of browns and greys by combining new synthetic oil-paint colors (colors we today take for granted) such as cobalt blue, cerulean blue, synthetic ultramarine, emerald green, viridian, chrome yellow, vermilion, and crimson lake. He also used touches of lead white and a little ivory black. No shadow was considered as being without color, and the deepest shadows are tinged with green and purple.

Trying to Observe Color
Monet described his attempts to observe and capture the colors in nature thus: “I’m chasing the merest sliver of color. It’s my own fault, I want to grasp the intangible. It’s terrible how the light runs out, taking color with it. Color, any color, lasts a second, sometimes three or four minutes at a time. What to do, what to paint in three or four minutes. They’re gone, you have to stop. Ah, how I suffer, how painting makes me suffer! It tortures me.”

Monet also said: “It’s on the strength of observation and reflection that one finds a way. So we must dig and delve unceasingly.” “When you go out to paint, try to forget what objects you have before you, a tree, a house, a field or whatever. Merely think here is a little square of blue, here an oblong of pink, here a streak of yellow, and paint it just as it looks to you, the exact color and shape, until it gives you own naïve impression of the scene before you.” Doesn’t he make it seem easy?