# Why color-wheel websites (Adobe...) claim these colors are complementary

I just learn about the different color harmony styles models, and I was playing with Adobe color wheel website using the complementary style, but I'm realizing that the proposed colors are not really on the other side of the Hue circle:

Here, you see that the blueish line has hue 174° and the brown color has hue 19°, and 174°-19°=155°, while I would expect their distance to be 180° since they are complementary. And if I ask to Krita, they are indeed not on opposite parts of the Hue circle:

So what's wrong with Adobe color wheel? I also tried with https://paletton.com, and the Paletton gives similar results compared to Adobe color. Are all color wheels crazy, or am I missing something? I also tried to check how footage was behaving, and they seem to agree with my definition, for instance this photo uses colors #27AB9E (Hue=174°) and #ff4473 (hue=344°), which are much more aligned, and we have 344-174 = 170° which is way closer to 180°.

• Adobe is probably using the CIE Lab* color space for determining hue, rather than RGB. Apr 24, 2021 at 19:54

Not all color wheels are alike. The traditional/old school RGB color wheel (like Krita's) begins with the three primaries at 120˚ intervals; which places red opposite cyan, such as this wheel.

However, more modern color wheels use the opponent process colors which places red/green and blue/yellow opponents at 180˚ intervals... such as the adobe color wheel.

And then there are other color wheels that use RBY which places those three colors at 120˚ intervals; it also places red opposite green, but blue is no longer opposite yellow. This wheel aligns with the color mixing principles taught in grade school (e.g. blue+yellow=green, blue+red=purple, and red+yellow=orange). However it breaks the CMY (subtractive colors) triadic relationship the other two color wheels maintain.

Which one is correct? I can't really say because it's all color theory. But my inclination is the opponent process theory.

• Oh, I see, thanks a lot. And is there any "mathematic/physical" reason to say that the opponents of red is green and that the opponent of blue is yellow, is it just a more or less arbitrary choice because it's more practical to work with an even number of colors and define pairs opponents? Also, if you have some cool resources on color grade theory, I'd be curious to hear about it! Thanks! Apr 24, 2021 at 13:47
• @tobiasBora Color is only meaningful in terms of how humans experience it. There’s nothing special about the visible spectrum except that it is meaningful to us. Color theory is based on human experience not the way things are independent of humans in the manner in which we reason about subatomic particles. And human vision is a messy product of evolution. Both biological and cultural. Apr 24, 2021 at 14:12
• @BobMacaroniMcStevens It make sense, sure. But I guess there must be some mathematical theories for colors, more or less independent of the human perception (or that only start from basic principle, like "if you mix blue and yellow, human will see green"). From that, I guess you can matematically define a "sum" operation between colors, and a "basis" which are some colors that are enough to represent all other colors. For instance, we can sum blue and yellow and obtain green, and you can physically observe it. So I'm wondering if there is a natural space in which red/green are "opposite". Apr 24, 2021 at 14:30
• @tobiasBora, The RGB color theory functions in the way optical receptors receive light information (short/med/long wavelength sensitive cone cells); and it is the basis behind the bayer CFA digital sensor and the LCD display. But the opponent process theory functions in the way our brains interpret that information and perfectly explains after images/colors. verywellmind.com/… Apr 24, 2021 at 19:51
• @tobiasBora, What you are seeing is additive colors balanced against subtractive colors; RGB offset against CMY; in that order... just like how a color balance adjustment layer, and temp tint adjustments work. It is pretty consistent for people with normal color perception (~85%). Too much information here... frontiersin.org/articles/10.3389/fnhum.2017.00229/full#B19 Apr 25, 2021 at 13:25

I try to avoid getting too complicated about these, for me I just focus in temperatures and keep it simple using context to find the right hues when I'm painting.

However,if you screengrab all these wheel examples,put them in photoshop and then invert colors ( ctrl+i) only the the old school rgb wheel will perfectly invert the wheel, keeping the same colors angles opposing each other,so I think that one is the most mathematically correct, because it colors turn into the exact color placed 180 grads across.

The thing is when working with real pigments it doesn't work like this, so I assume the other wheels try to imitate how real pigment works. I don't know thought

• It makes sense that an RGB operation on a RGB color wheel would be the most consistent. But I wouldn't take that as a sign of its inherent superiority - complementary colors are as much a psychological phenomena as a physical one. Oct 1, 2023 at 14:49