Colors are the basic elements of a painting, and every color has three sides to its personality: hue, value, and chroma. Gaining an intimate knowledge of the personalities of the colors you use is crucial in learning to paint.
We tend to simply call paint a particular color, whether it's a general description such as “light blue”, a more poetic like “aquamarine blue,” or quite specific such as “ultramarine blue”. A painter trying to mix a color on their palette to accurately match a color in their subject needs to consider hue, value, and chroma to mix color correctly.
At its most basic level, "hue" is artspeak for the actual color of a pigment or object. But the use of the term hue is more complicated when it comes to the names that paint manufacturers give their paint colors.
This is because the term “hue” is used to indicate that a color is not made from the pigment(s) that were originally used for that paint but modern equivalents that are either cheaper or more lightfast. Judging a hue is the first step in color mixing as it identifies what tube of paint to reach for.
Value or tone is a measure of how light or dark a color is, without any consideration for its hue. Think of it as taking a black-and-white photo of a subject where you clearly see what’s in the photo but everything is in grayscale.
The problem with a color’s value or tone is that how light or dark it seems is also influenced by what is going on around it. What appears light in one circumstance can appear darker in another circumstance, for instance when it’s surrounded by even lighter tones.
The chroma, or saturation, of a color is a measure of how intense it is. Think of it as “pure, bright color”, compared to a color diluted with white, darkened by black or gray, or thinned by being a glaze.
Variations in chroma can be achieved by adding different amounts of a neutral gray of the same value as the color you're wanting to alter.
Color mixing would be easier if the value and chroma were the same, but they’re not. With chroma, you’re considering how pure or intense the hue is, whereas with the value you’re not considering what the hue is at all, just how light or dark it is.
As a beginner, it's important to consider hue, value, and chroma when you mix colors. But the good news is that but with more experience, color mixing becomes an easier process.
Initially, it’s well worth taking the time to consider the hue, value, and chroma in a color you’re want to match, making a judgment or decision on each before you attempt to mix the color. You'll waste less paint reduce frustration by mixing the “wrong” colors.