May 18, 2018knowledge, opinions/rants, technologyadditive colour mixing, blue, color primaries, green, subtractive colour mixing, yellows.westland

So some civilization say yellow and blue do green. And also you will discover other answers that say the yellow and blue do black. How can this be?

Well, we require to understand a tiny science to acquire to the bottom of this.

You are watching: What color do blue and green make

The figure below shows what happens as soon as you mix perfect yellow colors with suitable blue pigment. The blue dye mirrors light perfectly in around a third of the spectrum (and absorbs perfectly in the other two thirds). The yellow pigment mirrors light perfect in about two thirds that the spectrum (and absorbs perfectly in the various other third).


Notice that with a real yellow colorant, it does no reflect perfect in the middle and also long wavelengths and it does no absorb perfectly in the short wavelengths. It reflects and absorbs to some level all the wavelengths however it absorbs an ext the shorter wavelength and also absorbs much less the middle and longer wavelengths. The exact same is true that a real blue pigment; that does no absorb perfectly at the middle and also longer wavelengths. The consequence of this is that you don’t obtain black if you mix blue and also yellow. You would get black if the pigments were ideal but they space not. Us live in the real world. However, you certainly don’t get a lovely bright green as presented in the colour wheel v red, yellow and blue primaries. You would gain a dark desaturated murky dirty greenish colour.

Now let’s check out what happens as soon as we mix cyan and yellow. We’ll start with the best colours.


That’s right. Mix cyan and magenta makes blue. The cyan absorbs in one 3rd (the red third) and the magenta absorbs in one 3rd (the green third) however neither absorb the short wavelengths.

So lastly you can see that the finest subtractive primaries room cyan, magenta and also yellow since the cyan is red absorbing, the magenta is green taking in and the yellow is blue absorbing. And what is more, girlfriend now understand why this is the instance (rather than accepting dogma). You additionally understand why over there is a relationship between the CMY the subtractive mixing and also the RGB of additive mixing.

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John R Reinert Nash says:

This short article focuses top top pigments, and also why CMY make an ext logical primaries because that pigments. The explanation is solid (as any press printer will tell you!), and also the RYB wheel together something teach in elementary school art class really does must be updated. If we can gain these men to execute a video on CMY, it would certainly go a lengthy way:

together a shade scientist who straddles the people of image capture (RGB!) and also print (CMYK and more!), however, we should absolutely continue to teach the yellow and also blue do green, however make it clear the this functions for light, and also not therefore well for paint. Ns recall the Kodak did dabble in CMY shade filters because that a digital camera, however RGB filter (Bayer filter in particular) for light really execute seem to have actually won the day for camera record (with some interesting experiments in adding an “emerald” 4th pixel color by Sony that never ever quite seemed to take it off).