Colour harmony basics for painters
Colour is often the hardest thing to get right from observation, because your eye adjusts to lighting far more than a camera or a measurement does. A little theory helps you notice what’s actually in front of you.
Hue, value and temperature
Hue is the colour family — red, blue, yellow, and everything between. Temperature is how warm or cool a colour reads, independent of hue: a warm blue and a cool blue can sit right next to each other in the same painting. Value, covered in a separate guide, is how light or dark a colour is regardless of its hue.
Why paintings go muddy
Muddy colour is almost always a temperature problem, not a hue problem. Mixing complementary colours (opposite each other on the colour wheel) in roughly equal amounts cancels out saturation and produces a grey-brown — sometimes exactly what you want, often not.
Matching your reference, not your memory
It’s easy to paint the colour you remember a subject having, rather than the colour it actually is under the light you photographed it in. A shadow on a “white” object is rarely grey — it usually carries the complementary temperature of the light source.
What plzxplain checks
plzxplain doesn’t measure hue or saturation directly today — reading colour accurately is still on you. What it does measure is value (the light-and-dark structure your colour choices sit on) and, in the edge engine, the temperature contrast across a transition, since a hard edge often carries a bigger temperature shift than a soft one. Get the temperature right and the value and edge critiques will make a lot more sense.