Charcoal vs Slate

Charcoal and Slate are both blues, but they are not the same color: the measured difference between their classic values is ΔE 21.8, clearly different colors.

Charcoal

RGB: 54, 69, 79
HSL: 204, 19%, 26%
OKLCH: 38.1% 0.026 237.5

Temperature: neutral, leaning cool (subtle blue undertone in this near-neutral)

Closest encyclopedia entry: Arsenic

Slate

RGB: 112, 128, 144
HSL: 210, 13%, 50%
OKLCH: 59.3% 0.031 248.3

Temperature: neutral, leaning cool (subtle blue undertone in this near-neutral)

Closest encyclopedia entry: Citadel

Measured difference: ΔE 21.8 · clearly different colors. ΔE is a measure of perceived color difference; below 2.3 most people can't tell colors apart.

Guide

How to tell Charcoal and Slate apart

1 Slate is measurably lighter (21 points of OKLCH lightness). Squint: the one that survives is Charcoal.
2 Their hues sit 11 degrees apart on the wheel. Put them on white side by side and the hue gap is the first thing you see.
3 Check them against a true neutral gray: subtle undertones surface immediately next to something with no undertone at all.

Guide

When to use which

Charcoal passes AA for text on white (9.9:1), so it can work in type and trim, not just surfaces.

Slate is a surface color: it needs a dark background before it can carry text.

Palettes

Their palettes, side by side

Charcoal complementary palette

Slate complementary palette

Charcoal analogous palette

Slate analogous palette

FAQ

FAQs

Are Charcoal and Slate the same color?

No. Using their classic reference values, they differ by ΔE 21.8 (a measure of perceived color difference; below 2.3 most people can't tell colors apart). That makes them clearly different colors.

Which is darker, Charcoal or Slate?

Charcoal is darker: 21 points lower in OKLCH lightness than Slate.