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

So some world say yellow and also blue do green. And also you will uncover other answers that say that yellow and also blue make black. How have the right to this be?

Well, we require to know a small science to get to the bottom of this.

You are watching: What do green and blue make

The figure below shows what happens when you mix perfect yellow pigment with suitable blue pigment. The blue dye reflects light perfect in about a 3rd of the spectrum (and absorbs perfectly in the other two thirds). The yellow pigment shows light perfectly in about two thirds that the spectrum (and absorbs perfect in the various other third).

*

Notice that v a actual yellow colorant, that does not reflect perfectly in the middle and long wavelengths and it does not absorb perfectly in the quick wavelengths. The reflects and also absorbs come some extent all the wavelengths however it absorbs an ext the much shorter wavelength and also absorbs less the middle and also longer wavelengths. The very same is true the a real blue pigment; that does no absorb perfect 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. Girlfriend would acquire black if the pigments to be ideal yet they space not. We live in the real world. However, you certainly don’t obtain a lover bright eco-friendly as shown in the colour wheel through red, yellow and blue primaries. You would gain a dark desaturated murky dirty greenish colour.

Now let’s view what happens once we mix cyan and also yellow. We’ll start with the appropriate colours.

*

That’s right. Mix cyan and magenta provides blue. The cyan absorbs in one third (the red third) and the magenta absorbs in one third (the eco-friendly third) but neither absorb the brief wavelengths.

So ultimately you can see the the best subtractive primaries space cyan, magenta and also yellow due to the fact that the cyan is red absorbing, the magenta is green taking in and the yellow is blue absorbing. And what is more, friend now know why this is the situation (rather than accepting dogma). You likewise understand why over there is a relationship in between the CMY that subtractive mixing and the RGB the additive mixing.

See more: How Many Atoms Of Nitrogen Are In 10G Of Nh4No3? ? How Many Atoms Of Nitrogen Are In 10G Of Nh4No3

*
John R Reinert Nash says:

This write-up focuses top top pigments, and why CMY make much more logical primaries because that pigments. The explanation is hard (as any press printer will tell you!), and also the RYB wheel together something taught in elementary college art class really does should be updated. If we can get these guys to perform a video on CMY, it would certainly go a long way: https://www.youtube.com/watch?v=yu44JRTIxSQ

as a color scientist who straddles the people of image catch (RGB!) and also print (CMYK and more!), however, we have to absolutely proceed to teach the yellow and blue do green, but make that clear that this functions for light, and also not therefore well because that paint. Ns recall the Kodak walk dabble in CMY shade filters because that a digital camera, yet RGB filter (Bayer filter in particular) for light really perform seem to have actually won the day for camera capture (with some exciting experiments in including an “emerald” fourth pixel shade by Sony that never quite seemed to take off).