What does the first number in hair color formulation indicate?

In hair color formulation, the first number is significant as it represents the level of the hair color. Hair color levels are measured on a scale from 1 to 10, with 1 being the darkest shade (black) and 10 being the lightest shade (light blonde). This indicates how light or dark the hair color will be after application. Understanding levels is crucial for hair colorists as it helps in achieving the desired shade based on the client's natural hair color and the endpoint effects they wish to accomplish.

Other components of hair color formulation, such as secondary pigment concentration, base color, and reflective quality, are also important but are indicated differently within the color formulation. Each of these elements affects the final color result but do not represent the foundational lightness or darkness of the color in the same straightforward way that the first number does.