Rainbow4

Summary

Rainbow4 is a sequential colormap from colorcet. Lightness spans 0.24–0.89, hue sweeps 237° from blue to red, and order breaks under protan and deutan simulation.

Perceptual profile (OKLCh)

• Lightness: 0.243 → 0.553 (range 0.645, min 0.243, max 0.889); non-monotonic; midpoint 0.742
• Chroma: min 0.092, max 0.262, mean 0.197
• Hue: 265.7° → 28.4° (span 237.3°), path monotonic-ccw; quadrants: blue, azure, cyan, mint, green, chartreuse, yellow, orange, red
• Endpoint temperature: cool → warm
• Perceptual ΔE: total 196.0, mean/step 0.769, max step 3.108, smoothness 0.291, speed 0.769

Colorblind safety (ΔE under simulated CVD)

• Protanopia: ΔE total 157.6; preserves order: no
• Deuteranopia: ΔE total 144.4; preserves order: no
• Tritanopia: ΔE total 151.1; preserves order: yes

Related

• Family: colorcet
• Source: Kovesi 2015 — "Good Colour Maps: How to Design Them" (arXiv:1509.03700)
• Similar sequential maps: Bgy, Bgyw, Blues (perceptual), Bmw, Bmy, CB-Kbw, CB-Kyw, CB-Kcw
• All colormaps