Chroma harmonization

Multi-hue palettes look unbalanced when one hue is more saturated than the rest at the same brightness stop — a neon outlier in a calm set, a washed-out blue next to a vibrant red. Chroma harmonization is the fix: at each stop, cap every hue at the lowest-achievable chroma across the set so the palette reads as a coherent family.

When to use

• Constructing a multi-hue palette (3+ hues at the same set of contrast stops).
• Auditing an existing palette where one hue looks "off" against the others.
• Generating UDTS's default harmony palette variant.
• Code review: flag per-hue chroma values picked independently — propose the cross-hue cap.

When NOT to use

• Single-hue palettes (no other hues to harmonize against — chroma is unconstrained by the procedure).
• Brand-spot or accent palettes where one hue should dominate. Use the max palette variant instead — see oklch-color-space.
• Palettes constrained to legacy sRGB-only output, where the narrower gamut shifts the bottleneck calculus back toward the classic blue-at-~220° limiter (the procedure still applies — Display P3 is the default target space; substitute the sRGB boundary deliberately for legacy-only catalogs).

The algorithm