In Pointillism, the artist uses small dots or strokes of paint to make up the pictures. From far away, these dots blend together to form the picture and give the impression of different colours as they blend together.
Georges Seurat developed the technique in 1886, branching from Impressionism. The term Pointillism was first coined by art critics in the late 1880s to ridicule the works of these artists.
Pointillism is a form of painting in which tiny dots of primary-colours are used to generate secondary colours. It is an offshoot of Impressionism, and is usually categorized as a form of Post-Impressionism.
The technique relies on the perceptive ability of the eye and mind of the viewer to mix the colour spots into a fuller range of tones and is related closely to Divisionism, a more technical variant of the method. Divisionism is concerned with colour theory, where pointillism is more focused on the specific style of brushwork used to apply the paint. It is a technique with few serious practitioners and is notably seen in the works of Seurat, Signac and Cros.
Pointillism is considered to have been an influence on Fauvism.
Sunday Afternoon on the Island of La Grande Jatte, Georges Seurat, 1884-1886.
Paul Signac (1863-1935)
The practice of Pointillism is in sharp contrast to the more common methods of blending pigments on a palette or using the many commercially available premixed colours.
http://www.webexhibits.org/colorart/index.html Good website on colour, how the eye sees colour, etc.