Thursday, February 1, 2018

Colour Management

Marc Edwards (via Gus Mueller):

Colour spaces are more complex than measurement units. They don’t just define a scale, they set a white point, range and scale for red, green and blue in the visible spectrum, as well as other various properties. There’s many ways to visualise colour profiles, but using a 3D hull is a common and useful way to display them.


However, there are some colours in the Display P3 space that are not in the sRGB space. Display P3 is wider gamut and it can represent more, especially deep reds and greens. #ff0000 in Display P3 can not be described as an sRGB HEX value, because it is out of the sRGB range.


On iOS and Android, sRGB is also the default, but both support wider gamut colours and colour spaces. On macOS, sRGB is sort of the default (the situation is a bit more complex due to some legacy issues).

Marc Edwards:

A colour space’s gamut defines the range of colours that can be represented by that colour space. It defines the extremities of how strong and pure colours can be.


Colour precision isn’t defined as part of a colour space. It is an implementation detail that’s left up to the rendering engine or design tool. This means different tools take a different amount of care, and the likelihood of problems is dictated by what you’re using as well as how you’re using it.


Unlike most rulers, the notches aren’t always evenly spaced. It is actually more common for them to be unevenly spaced. sRGB uses a non-linear gamma curve that’s like the image below. Other common colour spaces also use non-linear gamma curves. Display P3’s gamma curve is identical to sRGB’s gamma curve.

Update (2018-02-06): McCloudStrife:

“#ff0000 in Display P3” Get out.

I have also read Part 2 of this and I think the internet would be better off without either article tbh. Ignorance > misinformation.

Update (2018-03-15): Marc Edwards (tweet):

This article details the settings required for screen design in many popular design tools.

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