Blue Hour
Long sessionsInterfaces that open at dusk and stay open; the top step is a usable surface.
Click a swatch to copy its hex.
Do not use this for
Print — the range collapses on paper.
What was measured
- Closest neighbours
- ΔE00 12.5
- how alike two adjacent swatches look
- Darkest to lightest
- 8.56:1
- WCAG contrast across the set
- Lightness covered
- 55 pts
- of OKLCH lightness, 0–100
- Under colour blindness
- ΔE00 11.5
- worst under deuteranopia
These two are one colour to a reader with deuteranopia. Fine while the set is read as an order; never use them to mean two different things without a label or an icon as well.
A suggested mapping · derived, then measured
Five colours are not an interface, so this is an offer rather than a token set. It does not clear WCAG AA on the accent — stated here rather than left for you to discover.
/* Blue Hour — Interfaces that open at dusk and stay open; the top step is a usable surface. */
:root {
--palette-1: #1c1932;Tailwind
// tailwind.config — Blue Hour
export default {
theme: {For your coding agent · printed from the colours
Use the Blue Hour palette: #1C1932, #333C64, #486691, #7091AC, #A2BCC8. It is for this: Interfaces that open at dusk and stay open; the top step is a usable surface.
How this palette was built · no hex was chosen by hand
The catalog states a recipe — ramp from hue 258 — and the five colours are derived from it in OKLCH, where a step of lightness is a step your eye agrees with rather than one the hex numbers agree with. That is why the numbers above are properties of this palette rather than claims about it.