Keep brushes submerged in water while painting with acrylics.
Acrylic painting offers the color and modeling capabilities of oil painting, with a few significant differences: acrylic paints dry much faster than oil paints, clean up much easier, and offer a higher-keyed range of colors than those available in traditional oils. Due to their short drying time, artists cannot blend and layer acrylic paints in the same way as oil paints, so they do require a slightly different technique.
Preparation
You can apply acrylic paints to nearly any surface, but they will work best when applied to a properly primed canvas or panel support. Pre-made canvas boards and pre-stretched canvases work well for acrylic painting, because they are already primed with white acrylic gesso. If you prefer to stretch your own unprimed canvas, you can prime your canvas with a pre-mixed acrylic gesso. If you enjoy working on the bare canvas color, you can prime your canvas with acrylic flow resist or a coat of acrylic gel medium. Since acrylic paints are water-based, they do not have the same long-term damaging effects on natural fibers as oil paints, so they are a good choice for stain painting, or application directly onto unprimed canvas. When acrylic paints are applied to unprimed canvas, they soak into the fabric, and have a tendency to "spread," just as a coffee or water stain would on a shirt. For this reason, stain painting is not appropriate for highly detailed types of painting, but is often a technique in abstract painting.
Application
The key to success with acrylic painting is applying the paint with a sense of bravado-the quick drying time does not easily allow for correcting mistakes, so it’s best to approach acrylic painting with a bold mindset, not worrying about potential errors. Begin with a thin wash of color to block in the basic shapes of your painting, just as you would with oil painting. Thin the color with water on a large palette, mixing the paint and water thoroughly with a palette knife before application. The paint will dry quickly, and you can add successive layers directly on top of preceding layers. Unless you add the next paint layer very quickly, it will not blend much with the underlying layer, so mix your colors on the palette, rather than on the canvas itself. Correct any mistakes by simply painting over the previous layer.
Clean-Up
Clean brushes and tools thoroughly with clean water immediately after use, and keep all brushes immersed in water while working. Acrylic paint will dry very quickly on a brush, and can be very difficult to remove once dried. After a thorough cleaning with water, treat brushes with a brush-cleaning solution. Alternatively, you can use a mild dishwashing detergent to clean brushes. When cleaning brushes, take care to scrape all paint residue away from the hell of the brush (the area where the bristles attach to the ferrule). Paint can accumulate in this area, decreasing bristle flexibility over time.
