Although you can buy white watercolor paint, it looks a little chalky, and unless you're going for the unnatural look, you should avoid using it. Watercolor is very different from oil or acrylic painting where paint is applied for white areas.
It's a good plan to paint light areas first and continue with successively darker colors. Work from light to dark.
Use a white crayon or candle
One trick to preserving the white of your paper is to use wax. Wax resists watercolor, so using a white crayon or a candle is a quick and easy way to save a bit of white when painting. Say you don't want to go to the effort of painting around an area for a tiny highlight in a flower. Just a touch of a crayon saves the dot, stays invisible, and keeps you from needing a steady hand to paint around that highlight.Any substance that prevents or resists paint is known as a resist, and wax is one type of resist. (Colored wax acts as a resist, as well, but it obviously leaves a colored area on the paper, so unless that's the effect you're going for, be sure to use white wax.)
Steps to getting a wax resist
To save white in a painting with a wax resist, follow these steps:1. Find a white crayon or a white candle.
2. Draw on the watercolor paper using your crayon or candle.
Your design will be hard to see — invisible in fact. But if you tip the paper, you can see by the matte finish where you applied the wax.
In an actual painting, you'd put the wax anywhere you want to save a highlight, perhaps for a glint in an eye or a sunspot on a leaf. Just cover where you want white, but remember that the wax stays on the paper. If you want the paper clean later, use a masking fluid because it peels off after you've saved the white area.
3. Using a brush of your choice, paint over the top with a diluted paint of any color.
Voilá! Your secret design is revealed.
Preserving the white areas
Keep these points in mind when you use wax to preserve white in your watercolors:- The darker the paint you use over the wax, the more vivid your design will be.
- Smooth paper holds a better wax line. If your paper is really textured, the wax may not coat the paper entirely. If only the top surface of textured paper gets wax, the result is another spotty texture, which may be just the effect you're looking for.
- The wax stays on the paper because it's not removable. It's essentially invisible except for the waxy buildup. If used in small amounts, it may not be visible at all.