#BCD6FF · #BCE1B3
Four independent scores (read the one that fits your goal): Readability 1/100 (fail) · Harmony 89/100 (triadic) · Distinguishable 52/100 (somewhat similar) · Match 0/100 (different). There is no single “good/bad” — a pair can clash for text yet be great for an outfit.
Periwinkle and Seafoam are very different (ΔE 46). They have distinctly different hues (108° apart) and their lightness is similar, so they read as two same-weight colours.
Periwinkle text on Seafoam: 1.03:1 (Fail); Seafoam text on Periwinkle: 1.03:1 (Fail). Neither meets AA at body size — nudging one color to #485F82 clears it.
Triadic — triadic — a recognised, balanced pairing (harmony 89/100). This is about how they look together (clothing, interiors, branding), independent of text contrast.
Not at body size — the best direction is only 1.0:1, below the 4.5:1 minimum. Nudging one colour to #485F82 clears AA.
Their CIE76 ΔE is about 46 — very different.
clearly different colours (ΔE 46).
Explore each color: Periwinkle #BCD6FF · Seafoam #BCE1B3 · Shades: Periwinkle shades · Seafoam shades · Contrast checker →