What unit of measurement is used to assess the lightness or darkness of a color?

The unit of measurement used to assess the lightness or darkness of a color is referred to as "level." In the context of hair coloring, the level scale typically ranges from 1 to 10, with 1 representing the darkest black and 10 indicating the lightest blonde. This system allows hair colorists to precisely determine and communicate the desired lightness or darkness of a hair color.

While "shade," "intensity," and "tone" are related concepts in the realm of color theory and hair coloring, they do not specifically measure lightness or darkness. Shade refers to a particular color within a level, intensity pertains to the brightness or vividness of a color, and tone relates to the quality of color created by mixing a hue with gray. Understanding these distinctions is vital for effective communication and execution in hair coloring practices.