Color-washing is a technique used to create subtle tone-on-tone frescoes or dramatic contrasts on walls. Use an assortment of natural sea sponges to achieve marbleized swirls of color that you can stylize with a variety of techniques. Color-washing can have also have structure, such as a cloud color wash. It can be used to disguise minor wall damage, or add depth to an existing wall color. Start with a dark or light wall color. The colors chosen for your base and topcoats should be at least two shades apart on a paint color chip. Extreme contrasts create a stronger color-wash statement on your walls.
Apply one coat of the base color with a paint roller to all wall surfaces. Cut in as needed with a paintbrush in corners and around windows and doors. Use the base color to also paint a large board or piece of sheetrock for a test surface for your color washes and techniques. Allow all surfaces to dry completely. Your walls may require a second coat if the original color bleeds through after drying.
Measure and blend small amounts of the faux base and topcoat color to create several color wash samples, stirring thoroughly. Make note of each ratio for future mixes. Use a dry sponge to apply small amounts of each mixture to a portion of the sample board. Add more glaze to lighten the wash or increase the amount of the topcoat color to intensify the effect. Experiment with a few sponges to perfect the application technique on the test board. Use a dry sponge to blot excess glazing mixture with delicate strokes. Let each sample dry, repeating the process until you achieve your desired effect.
Blend the desired proportions of glaze and topcoat in a small bucket for wall application. For best results, work with 4-by-6-foot wall sections at a time. Use a combination of large and small sweeping clockwise and counterclockwise strokes, rotating and changing sponges to create a diverse, random color wash. Or use a more controlled application method to stylize clouds or to define a corner or architectural feature. Strive for creating a subtle patina of interesting tones and patterns that enhance the room's features. Follow behind with delicate blotting movements to absorb excess paint mixture and prevent runs. Let walls dry completely.
Add a third color wash to a clean, dry sponge, and apply the glaze mixture with random, delicate blots. Avoid large sweeping strokes to prevent heavy application, peeling or filmy appearance. If creating a blue and white sky fresco wash, add small accents of light gray or pale yellow wash to bring depth and realism to your clouds.