Scumbling

Scumbling is painting thin layers of opaque light color over dark colors, which gives a broken color effect. Scumbling is rather like glazing, but with light colors over dark. The colors mix optically rather than on the palette, and the result is shimmery, opalescent.

Stippling

Stippling is similar to scumbling but you are adding more texture than contrast. Same strokes of paint but you are working for a texture effect instead of a color effect.

Sponging

Is using a seas spong to create dimensional paint. It is similar to stippling but you are using a thicker surface and creating a more dynamic color and texture effect.

These three techniques should be used on a dry canvas or the under painting with a thick brush head. These techniques can be used with all types of paint but they work best with acrylic or oil.

Best practice would be to add the under painting. Under painting  is an initial layer of paint applied to a ground, which serves as a base for subsequent layers of paint. Then use these techniques to add more layers of detail to bring out the focal points of the painting. These techniques would be characterized as a more impressionistic style of painting. Impressionism is an art movement beginning in France in the 1870′s, founded by an individualistic group of artists including, among others, Claude Monet, Auguste Renoir, Alfred Sisley and Camille Pissarro; all concerned themselves mainly with the components of light and the immediate visual impression of a scene using unconnected colors that were to be mixed by the eye; bright colors and bold brushwork were often used to achieve these impressions.

When using these techniques in your paintings start small and always remember less is more. If you add to much texture and contrast to your work it can become very chaotic. I call it tunnel vision. Always keep the big picture and try not to get lost in adding more detail to your work.