Clouds are simple but can be dramatic on their own or as part of a larger work.
Painting realistic clouds involves more than just a blue sky background and white paint. Clouds can appear deceptively simple, but actually contain complex areas of light, shadow and texture. It's tricky--but possible--to create convincing clouds using either oil paint or watercolors.
Background
Make sure your background--the sky--is a realistic shade of blue. If you are using oil paints, you may want to use a glazing technique to create a sky that contains variations of hues. To create a glaze, mix glazing medium into the paint before loading your brush. Allow each layer to dry completely before adding subsequent paint layers. The trick to glazing is keep the paint thin with medium and to vary the hue slightly between layers, so that the finished product is varied in color and portrays a realistic sky. Be aware that a single glaze can sometimes take more than 24 hours to dry.
If you are painting with watercolors, achieving the proper proportions of paint to water is important to the final outcome. Before painting, have a good supply mixed of one or several shades of blue. Keep in mind that watercolor paints tend to dry to a shade that is lighter by 50 percent.
Clouds
Keeping an image of clouds handy for reference can be a useful aid in determining the placement of light and shadowed areas in the painting. When shaping your clouds, remember that clouds are not symmetrically shaped. Beginning artists sometimes make the mistake of opting for symmetry and, in losing variation, lose a realistic effect along with it. Clouds tend to tail off along some edges and appear more defined along others.
If you are painting in oil, pointed round and filbert sable hair brushes are recommended for their sturdiness and ability to create smooth paint strokes, but any round or pointed tip brushes should work fine. Use the glazing method, and work from light to dark. Though it may seem counterintuitive, avoid using pure white for your clouds. If your background is blue, try mixing a very light blue for the first glaze. For subsequent glazes, mix colors as they appear in your reference image--these may be light blue, dark blue, taupe or gray.
For watercolors, use a variety of larger-sized round and pointed round watercolor brushes--sable hair is preferable, but any high-quality synthetic hair brush will do. While the sky background is still wet, dip the brush in water and dab any excess onto a paper towel. Apply the brush in a rolling motion across the sky background. The blue pigment is lifted out, giving the appearance of transparent clouds in the foreground. Wash and dry the brush before applying the next color wash, which will be a darker color, such as taupe or gray for shadows on the bottom of the cloud. Use light blues for hues near the top of the cloud. Experiment with overlapping colors and with variations in hue to see what works best. Don't expect your first attempt to be perfect, but practice often and enjoy the results.
