Glossary

Quick Reference

Color Formats

• HEX — Six-digit hexadecimal code, e.g. #FF7F50
• RGB — Red, Green, Blue channels, each 0-255
• RGBA — RGB with alpha (transparency) channel
• HSL — Hue (0-360°), Saturation (0-100%), Lightness (0-100%)
• HSLA — HSL with alpha channel
• HSV — Hue, Saturation, Value (similar to HSL but uses value instead of lightness)
• CMYK — Cyan, Magenta, Yellow, Black — print color space

Color Theory

• Hue — The color itself, on a 0-360° wheel
• Saturation — How vivid or muted a color is
• Lightness — How light or dark a color is (in HSL)
• Value — How light or dark a color is (in HSV)
• Chroma — Color purity (similar to saturation)
• Tint — Color mixed with white (lighter)
• Shade — Color mixed with black (darker)
• Tone — Color mixed with gray (muted)

Harmonies

• Complementary — Colors 180° apart (opposite)
• Analogous — Adjacent colors (within ±60°)
• Triadic — Three colors 120° apart
• Tetradic — Four colors forming two complementary pairs
• Split-complementary — Base + two neighbors of the complement
• Monochromatic — One hue with varying lightness

Accessibility

• WCAG — Web Content Accessibility Guidelines (W3C)
• Contrast ratio — Luminance difference between two colors (1:1 to 21:1)
• AA — Standard WCAG level (4.5:1 for body text, 3:1 for large text)
• AAA — Enhanced WCAG level (7:1 for body text, 4.5:1 for large text)
• CVD — Color Vision Deficiency (color blindness)
• Luminance — Relative brightness used in WCAG contrast formula

Standards

• sRGB — Standard RGB color space for the web
• P3 — Wider-gamut color space used by modern Apple displays
• Delta E — Perceptual color difference metric
• CIE Lab — Perceptually uniform color space used for Delta E