In watercolor, the traditional technique involves the use of no white paint, instead depending on the white of the paper (i.e., areas with no paint on them) for whites and on dilution of paint to determine the value of any particular part of the painting. (There are, of course, ways to “cheat” by using white.)
In painting with oil, it’s standard to use white to lighten mixtures. White (whether lead white, titanium white, or zinc white) is incredibly useful as there are many colors that can’t be obtained without it. Contrariwise, there are also colors that can’t be mixed if you use white. White lightens, but it also cools (in most circumstances), decreases chroma (except when applied in small amounts with some cool colors), and increases opacity. There are some circumstances in which you want to lighten (increase the color’s value) without the other effects of adding white. For example:
- In traditional oil painting technique, it is often appropriate to keep shadows transparent. That basically means mixing shadow colors without any white.
- Because white usually decreases chroma, mixtures involving white can be lower in chroma than you want. As a result, painters sometimes complain of paint mixtures that are too “chalky.” They get lights that have a pastel look with low chroma. While that is sometimes exactly the right color (in which case no one complains) we sometimes want lights that are as high in chroma as possible.
While oil painters don’t generally depend on white-freen paint mixtures to nearly the degree that watercolor painters do, it’s important to know how to paint without white when you need to. If you just need a dark color, that’s easy. If you need to paint a range of values, then you’ll need to find mixtures that achieve that value range. The ease of doing so depends on what part of the color wheel you’re working with.
There are plenty of high-value yellows, for example. If you need to lighten a yellow or brown mixture, you can usually do so by mixing in a lighter yellow (I like lead-tin yellow for this purpose, or a cadmium yellow if I’m looking for higher chroma). Reds are more difficult—it’s hard to mix a light red without dropping the chroma (i.e., making it pink). Genuine vermillion is sometimes useful because it is somewhat light and doesn’t drop chroma in mixtures the way cadmiums of similar color can do. Oranges can be lightened by adding a lighter yellow and then, if necessary, adjusting back to the right hue with a bit of red. A yellow green can similarly be lightened with yellow.
Cooler colors (blue, green, blue-green, purple) are more difficult to lighten, since the tube colors in this range are often pretty dark. Some cobalt blues can be relatively light and therefore quite valuable (although they are also opaque, so they don’t help as much if you are looking for transparency).
The other solution, of course, is to paint thinly onto a white surface, just as in traditional watercolor. The method used by Ted Seth Jacobs and his students such as Tony Ryder, for example, typically begins with a “color wash.” That means applying the first layer of paint very thinly, mixed with dilutant. While wet, the color can be lightened by wiping away paint with a dry rag or brush; or one dipped in dilutant. In this method, the initial color wash layer is later painted over with opaque paint mixed with white. A similar method can be used with traditional glazing technique or when a certainly watercolor-ish look is desired.
If you’re not used to painting without white, a good exercise is to try to complete a painting while using white only when absolutely necessary. That can generate an overall range of value and chroma that is markedly different than a painting in which white is used liberally. If you struggle with “chalky” mixtures, a minimal white approach can really help.