Nightfall

Summary

Nightfall is a diverging colormap from tol. Two arms meet at a pivot of lightness 0.93, hue sweeps 215° from cyan to red, and order holds under all three colorblind simulations.

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
• Pivot: t 0.502, lightness 0.934, hue jump 10.8°, smoothness 0.823
• 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: tol
• Source: Paul Tol, "Colour Schemes" (SRON/EPS/TN/09-002)
• Similar diverging maps: BuRd, PRGn, Sunset
• All colormaps