In the late 1860s, Claude Monet (1840-1926), Pierre-Auguste Renoir (1841-1919) and others painted in a new style, called Impressionism by contemporaries. The name was first used by critics, viewing a new exhibition held in 1874, and was directed precisely — and derisively — at a painting by Monet of a harbor at dawn, which he titled Impression: Sunrise. This painting is a striking example of the new style. How did Monet achieve the effect in this particular painting?

The sun is set against the dawn, the orange color against the gray and the vibrant force of the sun against its motionless surroundings. To many spectators, the sun undulates or pulsates slightly. Why is this so? The sun is nearly the same luminance as the grayish clouds. Notice how the sun nearly disappears if you remove the color. (Click painting to reset.) This lack of contrast explains the painting’s eerie quality.

The sun is perceived differently is different parts of our mind. To the more primitive subdivisions of our brain, the sun is nearly invisible. But to the primate subdivision, the sun appears normal. Thus, there is an inconsistency between our perception of the sun in the primitive and primate portions of our brain. The sun is poorly defined and ambiguous to the portion of our brain that carries information about position and movement.

If Monet had painted the sun brighter than the clouds (as indeed it is), the painting might be less interesting. If you artificially make the sun brighter or darker (as it is in reality), the primitive brain sees it better. But does that make the painting better or worse?