Color Wheel

The color wheel is not one thing. It is a family of circular hue diagrams, each optimized for a different use case. The painter's wheel (RYB) organizes hue around red, yellow, and blue primaries. The additive wheel (RGB) organizes around red, green, and blue for light-based work. The HSL and HSB wheels organize around perceived hue and are the default in most design tools. Modern perceptual wheels (OKLCH, HSLuv) organize hue by perceived uniformity across brightness. For working designers, the wheel's value is relational. Colors opposite each other are complementary (high tension, used sparingly). Colors adjacent are analogous (calm, family-like). Three evenly spaced colors are triadic (high energy). One color plus the two adjacent to its complement is split-complementary (balanced). These relationships are the vocabulary for proposing and evaluating palettes. The wheel becomes less useful the moment you need to reason about contrast, accessibility, or systematic token roles. It has nothing to say about perception, value, or WCAG ratios. That is fine. The wheel's job is hue relationships. Contrast, accessibility, and roles live in other layers of the color stack. When picking colors for a real palette, use the wheel to spot which proposed combinations are already harmonized, then move down the stack to evaluate perception, contrast, and palette construction.