Chart Color System
Solve, audit and simulate colorblind-safe chart palettes.
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What it can do
What data it sees
Do you need an account
No: the server works without sign-in
Solve, audit and simulate colorblind-safe chart palettes. WCAG contrast, OKLab ΔE. Read-only.
Server tool list (4)
Raw names from tools/list. Only developers need these.
| solve_palette | Generate a categorical chart palette of n colors (1-12) that maximizes perceptual separation under normal vision and colorblindness, with the given brand colors locked as anchors in slot order. Returns the palette, the worst pair distances, the engine's relaxation notes, a full accessibility audit against the background, and a link to open it in the app. Honest cap is 6 slots; above that the result says so. |
| audit_palette | Audit existing chart colors for accessibility: pairwise OKLab separation under normal vision, deuteranopia, protanopia, tritanopia and achromatopsia, plus WCAG 2.2 non-text contrast (3:1) of every color against the chart background. Returns a pass / warn / fail verdict with the numbers behind it. Set ramp=true for sequential or diverging scales, whose steps are meant to be close. |
| simulate_palette | Show what each color looks like to readers with deuteranopia, protanopia, tritanopia or achromatopsia (published Machado 2009 matrices), so an assistant can describe or render the palette as a colorblind reader sees it. |
| build_ramp | Build an evenly spaced perceptual (OKLab) color scale: sequential from start to end, or diverging from start through mid to end. Returns the steps and a background-contrast audit (pairwise separation is not judged for ramps). |