# Nightfall

Canonical URL: https://colorcurio.us/colormaps/tol.nightfall
Source type: Colormap
Type: diverging
Collection: tol
Attribution: Paul Tol, "Colour Schemes" (SRON/EPS/TN/09-002)
License: BSD-3-Clause
Source: https://sronpersonalpages.nl/~pault/
Tags: diverging, cvd-friendly, blue-red
Stops: 256

## Summary

Nightfall is a diverging colormap from the tol collection. Inspect its perceptual lightness, chroma, and hue profile on colorcurio.us.

Diverging blue→red with dark midpoint; designed for SRON/Tol set.

## Perceptual profile (OKLCh)

- Lightness: 0.425 → 0.454 (range 0.509, min 0.425, max 0.934); non-monotonic; midpoint 0.934
- Chroma: min 0.007, max 0.215, mean 0.107
- Hue: 189.3° → 28.6° (span 215.1°), path monotonic-ccw; quadrants: cyan, azure, blue, chartreuse, yellow, orange, red
- Endpoint temperature: cool → warm
- Perceptual ΔE: total 155.0, mean/step 0.608, max step 0.817, smoothness 0.876, speed 0.608

## Colorblind safety (ΔE under simulated CVD)

- Protanopia: ΔE total 139.3; preserves order: yes
- Deuteranopia: ΔE total 132.3; preserves order: yes
- Tritanopia: ΔE total 140.1; preserves order: yes

## Related

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