Paint colors should be one to three tones apart in the manufacturer's color-chip system. The base coat can be dark with light tones on top, light covered by darker tones, or a medium tone covered by both dark and light. As for the colors themselves, the more different the more dramatic.

After the base coat has dried, dampen the sponge, but not enough to thin the paint. Dip the sponge into the paint tray, blot off the excess onto a piece of cardboard, and then begin applying to the surface. Dab the sponge straight onto the wall without wringing or twisting it, applying the paint to random spots; the result should look "cloudy," allowing the base coat to show through. Turn the sponge clockwise to varying degrees to achieve a varying pattern. After the first topcoat dries, apply the second color the same way, allowing the sponge prints to merge together but also allowing plenty of the base coat to remain visible.

For the final coat, dilute the paint used for the base coat until it is very thin and translucent. (With latex use water; with oil-based paint, use thinner.) Dab this final "wash" over the wall lightly, overlapping the other coats, creating an overall blending effect.

Color washing gives a more rustic, aged look; it's beautiful with unpretentious pine woodwork or country-style furniture. This process involves multiple topcoats diluted very thin. The base coat should be white and the colors should be in varying tones of the same color family or two closely related color families.

For ideal transparency, you'll want to dilute latex paint at about nine parts water to one part paint in your paint tray. Apply the first colored coat with a flat brush, taking care to dab out any obvious hard edges and allowing the background to show through. Allow it to dry overnight and apply subsequent coats the same way. As a final coat, you'll want to apply a protective coat of clear polyurethane varnish that will make the surface washable.