Eli5: the difference between situation and chromacity in colour theory.


As far as I can tell they are effectively the same thing but everything I read online is trying to convince me they are different.

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Anonymous 0 Comments

Do you mean ‘saturation’ rather than ‘situation’?

Chromaticity is a description of a colour.

There’s ‘hue’ – what colour is it? Red, blue, yellow etc.

The TV test signal ‘colour bars’ here:


shows the primary and secondary colours (as well as black and white which we can ignore because chromaticity doesn’t apply to black, white or shades of grey). They’re all different hues.

There’s ‘saturation’ – is is a really vivid colour, or faded and washed out.

An example of a colour saturation is here:


There’s another aspect to things we see (which isn’t technically chromaticity), called luminance. This could be described as the brightness or darkness of something (and it’s applicable to monochrome / grey / black & white things, unlike hue and saturation).

An example of a high-luminance thing would be this bright red colour sample:


and a low-luminance red would look like this:


Note that hue, saturation and luminance exist and vary in isolation from one another.