Oklab on Tartan Dictionary

Where the Rainbow Sits in OKLab

Tue, 14 Jul 2026 00:00:00 +0000

The dictionary does all of its colour reasoning in OKLab — classifying shades, measuring ΔTartan, drawing dye-range maps. Those maps always show colours inside a gamut. This story asks the opposite question: where is the outer edge of all physically possible colour — the locus of pure monochromatic light, the curve that draws the famous horseshoe of the CIE 1931 chromaticity diagram — when you plot it in OKLab?

The fine grid — a colour space sampled evenly

Sat, 13 Jun 2026 00:00:00 +0000

A specifier book like Pantone or Munsell samples colour space unevenly — densely where its trade cares, thinly elsewhere — because it is a record of what people actually made. The Dictionary needs the opposite: a frame in which equal distance is equal perceived difference, filled evenly, so that "how far is this shade from that one" has a single honest answer. That frame is the fine grid.

What it is

Take OKLab — the perceptual colour space the colour list already uses — and simply fill it at one spacing in every direction:

The six-colour reference palette

Sat, 13 Jun 2026 00:00:00 +0000

The Dictionary names every pattern in a simplified six-colour vocabulary — white, black, red, green, yellow, blue, "the rest are shades of these six." These are not screen primaries (tartans are not woven in #FF0000); they are representative cloth shades, chosen to maximise discrimination — to keep the colour distinctions that genuinely separate one tartan from another and throw the rest away. This post re-anchors those six onto the fine grid and re-runs the experiment that picked them.