Chroma or saturation refers to the intensity, purity and degree of vividness of a color. A bold, intense red is a high chroma color while pastels are low chroma. Colorants with high chroma are called “brilliant” or “vivid.”
High chroma colors are more difficult to achieve in nature and therefore tend to be more expensive. They are also more likely to fade over time. Thus, when choosing a color, it is important to consider both its chroma and lightfastness.
Some colors naturally have higher chroma than others. For example, The brightest and most intense reds are found in nature in flowers such as poppies, while more muted shades of red can be found in leaves.