Being able to create realistic-looking drapery using oil paints is evidence of serious artistic skill and experience. It is a challenge that eludes many artists. The major difficulty associated with painting authentic-looking drapery involves the failure to accurately mix colors. Understanding texture is another critical aspect of the process that frequently goes overlooked. While the general rules for painting drapery are essentially simple, even formulaic, it is not something that can be easily done the first time. Practice is paramount.
Create a color scale. A color scale is essentially a swatch of shades that an artist paints on a piece of paper. This swatch shows how the color moves from pure white to pure black. Start with a single color such as purple. The color is placed in the center of the page and a miniscule amount of white or black is added to slightly lighten or darken it. This lighter or darker color is added to either side of the original color. More white or black is added a small amount at a time to the color mixture until only white or black remains. Each slightly darker or lighter color is shown on the paper as a swatch placed next to the last color.
Use a reference photo and draw the draperies as you see them in the picture, including the folds or piles of cloth.
Look at how the color of the draperies in your reference photo varies. The texture of the cloth, angle of lighting and folds will all have an effect on color. Even if you look at the image and your mind sees blue, there are a huge variety of shades of blue within that blue color.
Paint the body of the draperies using one of the middle shades. As a general rule, folds tend to be darker than the body of the drapery so paint them last.
Add texture and depth to the image. Use lighter colors to show highlights or spots where the cloth is reflecting light. A stiff square brush can be used to add texture and detail along the body of the draperies. After you have painted the body, avoid brushing up-and-down or from side-to-side. Draperies are all about texture and painting from side-to-side or from up-to- down will flatten the desired texture. Use the tip of the brush to apply color and small round-tip brush to create details.