Effets de soir (also called effets de soir et de matin) are the effects of light caused by the sunset, twilight, or darkness of the early evening or matins. They appear frequently in works by such painters as Vincent van Gogh, Bernhard Fries, Armand Guillaumin, and Camille Corot. Literally, it means "effects of evening" in French. This was part of a group of techniques used by Impressionists such as impasto, en plein air, color theory, and thick strokes of oil paint on canvas.