Snowflake

One ΔE for all directions is a sphere; real acceptance is a box. The Snowflake finds the box: six variants on the axes — lighter, darker, redder, greener, yellower, bluer — and you move each one until the difference is just acceptable.

How to use it

Every arm starts 6 units out, far enough to be plainly wrong. Press − on an arm until the variant is something you would accept, and + if you went too far. Do it for all six without looking at numbers — the judgement is visual, and numbers bias it. Then Reveal values: each arm shows its delta, and Details lists the three axes.

What you get

Three numbers that are yours, for this colour, on this paper, under this light: how far it may go lighter or darker, redder or greener, yellower or bluer. Written into a specification they are worth more than one ΔE, because they say where the danger is. Expect the L* arm to end closest to the aim and the b* arm furthest.