# Observable 10

Canonical URL: https://colorcurio.us/colormaps/d3.observable10
Source type: Colormap
Type: categorical
Collection: d3
Attribution: d3-scale-chromatic (Mike Bostock and contributors)
License: ISC
Source: https://github.com/d3/d3-scale-chromatic/blob/main/src/categorical/observable10.js
Tags: categorical, choropleth
Stops: 10

## Summary

Observable 10 is a categorical colormap from the d3 collection. Inspect its perceptual lightness, chroma, and hue profile on colorcurio.us.

Observable Plot default; tuned for both light and dark backgrounds.

## Perceptual profile (OKLCh)

- Lightness: 0.548 → 0.679 (range 0.249, min 0.548, max 0.797); non-monotonic; midpoint 0.652
- Chroma: min 0.013, max 0.208, mean 0.129
- Hue: 265.6° → 264.5° (span 276.8°), path folded; quadrants: blue, yellow, orange, mint, green, rose, magenta
- Endpoint temperature: cool → cool
- Perceptual ΔE: total 362.5, mean/step 40.275, max step 71.797, smoothness 0.555, speed 1.000

## Colorblind safety (ΔE under simulated CVD)

- Protanopia: ΔE total 265.0; preserves order: no
- Deuteranopia: ΔE total 261.3; preserves order: no
- Tritanopia: ΔE total 348.0; preserves order: no

## Related

- Family: https://colorcurio.us/colormaps/families/d3
- All colormaps: https://colorcurio.us/colormaps