Impressionist techniques

* Short, thick strokes of paint are used to quickly capture the essence of the subject, rather than its details. The paint is often applied impasto.
* Colours are applied side-by-side with as little mixing as possible, creating a vibrant surface. The optical mixing of colours occurs in the eye of the viewer.
* Grays and dark tones are produced by mixing complementary colours. In pure Impressionism the use of black paint is avoided.
* Wet paint is placed into wet paint without waiting for successive applications to dry, producing softer edges and an intermingling of colour.
* Painting in the evening to get effets de soir - the shadowy effects of the light in the evening or twilight.
* Impressionist paintings do not exploit the transparency of thin paint films (glazes) which earlier artists built up carefully to produce effects. The surface of an Impressionist painting is typically opaque.
* The play of natural light is emphasized. Close attention is paid to the reflection of colours from object to object.
* In paintings made en plein air (outdoors), shadows are boldly painted with the blue of the sky as it is reflected onto surfaces, giving a sense of freshness and openness that was not captured in painting * previously. (Blue shadows on snow inspired the technique.)
Painters throughout history had occasionally used these methods, but Impressionists were the first to use all of them together, and with such boldness. Earlier artists whose works display these techniques include Frans Hals, Diego Velázquez, Peter Paul Rubens, John Constable, and J. M. W. Turner.

French painters who prepared the way for Impressionism include the Romantic colourist Eugène Delacroix, the leader of the realists Gustave Courbet, and painters of the Barbizon school such as Théodore Rousseau. The Impressionists learned much from the work of Jean-Baptiste-Camille Corot and Eugène Boudin, who painted from nature in a style that was close to Impressionism, and who befriended and advised the younger artists.

Impressionists took advantage of the mid-century introduction of premixed paints in lead tubes (resembling modern toothpaste tubes) which allowed artists to work more spontaneously, both outdoors and indoors. Previously, painters made their own paints individually, by grinding and mixing dry pigment powders with linseed oil, which were then stored in animal bladders.