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Comment by eru | Hacker News Reader

You can get out of that argument by saying that colour names apply in different amounts to different hex-colours.

So #FF0000 is red. But is #FA0101 is also red, just slightly less so.

That's interesting. So what you have is some sort of similarity metric that is colour based. You could define it as being 1 for an exact match, and 0 for not matching, so cyan, etc. would be 0 red, while orange may be slightly red (e.g. 0.1), and pink may be slightly more red (e.g. 0.25). This would be a 3D function/surface.

This would allow you to model classes of colours, like purples. Shades of a colour could then be any similar colour in the range 0 to 0.5 (or 0.25).

Yes, this is what Delta E in the CIELAB color space is meant for. But in RGB color space this concept doesn't make sense; well, only if you would accept a non linear similarity metric - but then what is the metric for, if you need to apply a curve to it to normalize it? But still, this is different from modeling 'shades' of a color (if we say 'shades' are varying brightness in RGB space using the 0.21/0.72/0.7 brightness conversion - but again, I argue that 'shades' is an ambiguous concept).

My point is, again, that colors are a much more difficult concept than some in this discussion are making it out to be, and 'distance between colors' is more complex still.

Yes, agreed.

Yep, in fact, that’s exactly what those hex codes are: a specification for how much red, how much green, and how much blue is in the color (though our vision and color perception may not map linearly to that specification).

Sort-of. My aim was to suggest looking at natural clusters of similar shades.

You can map those clusters into RGB space. Or other colour spaces.

Technically you are correct, but I don't think that's what the colour-namers are going for.

That restricts you to 8 bits per color channel, and more importantly, to the RGB color space which is non linear. Comparing colors in RGB color space is nonsense in the first place ('comparing' here is 'judge by human perception'). 'Comparing' colors is just not that easy; in fact, I'd argue that without (much) more definition and clarification, it's impossible to do, because it can mean different things depending on the purpose.

I only used RGB and 8 bits per channel in the example.

My argument was more general.

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