How is complementary color determined?

[hfhska]

The complementary color is the one that is opposite on the color wheel, so to get its hue we need to add or subtract 180° (360/2) from the given hue. For example, the complementary of red (hue = 0) is green (hue = 180). But it seems that Adobe Color uses some different algorithm, because the complementary colors are not 180 apart in their hue. For example, when creating a complementary color scheme in Adobe Color, the complementary of red (hue = 0) is the color with hue 137. What is the logic behind this? Any insight is much appreciated!

[Iago28763357erss]

I also bumped into this. After much Wikipedia y finally found out about the RYB color model, the traditional one used for pigments in art. The RGB model is more scientific, and the hue angle is based on it. Adobe Color seems to use a model transform from RGB to RYB to apply color harmony rules. So the complementary of a color is 180° appart in the RYB model, and then it gets transformed into RGB, so you get those unexpected values in Hue, Saturation and Brightness. I hope someone can confirm this.

[syed_mehadi · Accepted solution]

That is correct. Hue in RYB wheel is different from hue in HSB wheel. Harmonies in Adobe Color are based in the RYB wheel. But some other creative tool uses HSB color pickers, Color's interface converts to and exposes the H from HSB for compatibility. Otherwise, when copying RYB hues everywhere else, colors would be wrong.

it is technically correct as per the underlying RYB wheel.