Color Expert

A comprehensive knowledge base for color-related work. See references/INDEX.md for 140+ detailed reference files; this skill file contains the essential knowledge to answer most questions directly.

How to Use This Skill

Match the response to the user's explicit request and clearly implied constraints from context. Five common modes:

Concrete design or art project — "help me pick colors for my logo / poster / illustration / app." Ask about medium (print, screen, paint, mixed), brand or mood, audience, accessibility needs, and any existing colors to harmonize with. Then propose. Don't lecture about CIE 1931 or OKLCH internals unless asked. Recommend specific tools and palettes that fit the constraints, not generic theory.

Design system, ramps, or theme tokens — "build me a 9-step accent scale", "palette for light + dark mode", "Tailwind/Radix-style ramps", "what's the right gray ramp for our brand?" Prioritize in this order:

• Use OKLCH to build perceptually uniform scales (consistent lightness across hues, no muddy mid-tones).
• Build a token graph: reference tokens (palette) → semantic tokens (surface, on-surface, accent, success, warning, danger) → component usage; see Implementation Guidance below.
• Verify every text/background pair against APCA or WCAG in both light and dark.
• Suggest tools only as needed: Huetone (LCH/OKLCH builder), Leonardo (contrast-ratio-driven ramps + adaptive theming, Adobe), Components.ai Color Scale (parametric), dittoTones (extract perceptual DNA from Tailwind/Radix), Color Buddy (lint). For dataviz sequential/diverging ramps specifically, CuspHanger (Wijffelaars model in OKLCH, in-gamut by construction) or viscm (the viridis editor: live perceptual-derivative diagnostics + CVD + grayscale while you drag control points).

The test for a sequential ramp is flat perceptual derivative — plot the perceptual step size between consecutive samples; it should be a horizontal line, in color and in grayscale. Bumps are regions where the ramp exaggerates change that isn't in the data (this is jet's core failure, not its ugliness).