Show HN: What's my JND? – a colour guessing game • Hacker News Board

OisinMoran wrote: post #33

This is fun! I just played once and got 0.0016, which it says is "absurdly below the theoretical limit"... Okay, tried again and got 0.0034 which is still says is beyond the human limit! I'll have to give this to my mum because we often argue about colours and I suspect she might be a tetrachromat. Both tests on a Pixel 10 btw

This test is subject to the display regime on which it's presented. A given display may hide or amplify differences due to lack of conformance with the color space for the test data.

Re: Show HN: What's my JND? – a colour guessing game

#65

Post by _wire_ » Thu, Mar 12, 2026, 7:54 PM UTC

patrakov wrote: post #15

erikig wrote: post #10

On a good monitor, I got to 0.0032 and then it all fell apart. Here's the related article on how much accuracy is really needed in CSS values. https://www.keithcirkel.co.uk/too-much-color/

It's worse. The code contains a function that, given the target ΔE, generates two colors in floating-point Oklab representation, separated by that distance. But there is no check whether the two generated colors end up rounding to exactly the same one on 8-bit displays. So, I was asked to find a boundary (while the claim was that there were two distinct colors 0.0013 ΔE apart) between RGB(80, 83, 152) and RGB(80, 83,…

Thx for heads up!