In color, value means lightness or darkness. A bright yellow has high value. A deep navy has low value. It has nothing to do with how expensive the color is. Value is about luminance, how much light the color reflects or emits.

Value is the most important dimension of color for readability. High-value text on a low-value background reads easily. Low-value text on a high-value background also works. But two colors with similar values will blur together, no matter how different their hues. Red text on a green background is hard to read if both have the same value. Change the value and suddenly it works.

Why value matters

• Creates contrast for readable text
• Defines form and depth in an image
• Works independently of hue
• Can be checked in grayscale

A common designer trick is to convert a design to grayscale and check the value structure. If it still reads clearly, the design has good value contrast. If everything turns into a gray mush, the colors are too similar in value. Value is also how we perceive shape and volume. A sphere looks round because of the value gradient across its surface. Strip the value away and it becomes a flat circle.