RGBは、赤、緑、青という3つの基本要素（またはチャネル）を混ぜ合わせることで表現されるカラーモデルです。各色は、最終的な色を決定する際、赤、緑、青それぞれの強度を示す3つの数字のシーケンス (通常は0.0〜1.0、または0〜255) で表されます。
There are many ways to describe the RGB components of a color. In {{Glossary("CSS")}} they can be represented as a single 24-bit integer in hexadecimal notation (for example, #add8e6 is light blue), or in functional notation as three separate 8-bit integers (for example, rgb(46, 139, 87) is sea green). In {{Glossary("OpenGL")}}, {{Glossary("WebGL")}}, and {{Glossary("GLSL")}} the red-green-blue components are fractions (floating-point numbers between 0.0 and 1.0), although in the actual color buffer they are typically stored as 8-bit integers. Graphically, a color can be represented as a point in a three-dimensional grid or cube, where each dimension (or axis) corresponds to a different channel.