There are two types of sponge painting: sponging on and sponging off. Both require the use of a sponge, but as the names suggest, the former involves applying a glaze to the walls with a sponge, and the latter method uses a sponge to remove glaze from a wall.
For a porous look, opt for sponging on. To achieve this look, begin by applying a base coat of semi-glass paint to the walls. Once the base coat dries, dampen a sea sponge and wring out the excess moisture. Use a paintbrush to apply glaze to the sponge and gently press the sponge onto the wall in a haphazard pattern.
Sponging off creates a more subtle look than sponging on. This faux finish technique also requires applying a base coat to the walls. Once the base coat has dried, paint glaze directly onto the walls. Press a slightly damp sea sponge in a random pattern onto the glaze while it is still wet. To prevent having the glaze dry before you are able to sponge off, work in small sections -- applying the glaze and then sponging off and moving to another section when finished.
Use this faux finishing technique to create the look of floating color. Apply a base coat to the walls -- an eggshell or a cream works well. Select a color glaze. Once the base coat has dried, apply the glaze with a paintbrush. While the glaze is still wet, use a rag to spread it around the wall; this creates the color wash effect, as the rag spreads the color of the glaze over the wall. You may need to repeat the glazing step a few times to achieve the look that you desire.
Create a subtle, textured pattern on your wall with a combing faux painting technique. As with the previously mentioned techniques, you will begin by painting a base coat on the walls. Choose a color that you like, as it will be seen in the end result. When the base coat dries, use a paint brush or a roller to apply glaze to a section of the wall. While the glaze is wet, run a rubber paint comb over it, removing the color of the glaze and allowing the base color to come through. You can run the comb in any direction you'd like -- horizontally, vertically or diagonally -- depending on the look you want to create.