Colour Mixing

According to YouTuber “minutephysics”, computer colour is broken. ( source )

We perceive lightness in a logarithmic way. We’re better at noticing difference in luminsity of darker colours. This fact was exploited in the early days of digital imagery and luminosity is stored non-linearly.

Once we start mixing colours, this non-linear way of storing values creates untrue values, often resulting in a gray-ish or brown-ish colour in the middle. The fix? Square the original colours before mixing them so lightness becomes linear again, and calculate the square root after to return to the optimised non-linear way of displaying colours on screens.