system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did cyan and magenta replace blue and red as the standard primaries in color pigments? What exactly makes CMY(K) superior to the RYB model? And why did yellow stay the same when the other two were updated?

I'm tagging this as physics but it's also to some extent an art/design question.

**EDIT:** to clarify my questions a bit, I'm not asking about the difference between the RGB (light) and CMYK (pigment) color models which has already been covered in other threads on this sub. I'm asking why/how the older Red-Yellow-Blue model in art/printing was updated to Cyan-Magenta-Yellow, which is the current standard. What is it about cyan and magenta that makes them better than what we would call 'true' blue and red? And why does yellow get a pass?

**2nd EDIT:** thanks to everybody who helped answer my question, and all 5,000 of you who shared Echo Gillette's video on the subject (it was a helpful video, I get why you were so eager to share it). To all the people who keep explaining that "RGB is with light and CMYK is with paint," I appreciate the thought, but that wasn't the question and please stop.
gpt
Red Yellow Blue was used in early printing because that was the best they knew at the time. Technology advanced, and printing color images switched to using magenta and cyan to get a wider, more accurate range of colors.

Our eyes see three basic colors of light: Red, Green, and Blue. Cyan pigment only absorbs one color from light, Red; this leaves behind Blue and Green. Magenta pigment absorbs only Green. Yellow pigment absorbs Blue. Mix those three in varying combinations and you can get every color the human eye can perceive. (Technically you don't need Black in CMYK, but it takes a lot of CMY to get a good, dark Black.)

In contrast, Red Yellow and Blue can only be mixed to *most* visible colors, but there are some that are simply not possible to create with those three as your "primary" colors.

The reason Yellow "gets a pass" is because it is a primary color in color schemes for both subtractive light and traditional art.

So why did we use Red Yellow Blue for so long? Because (a) for a long time we didn't know enough about light to know Cyan and Magenta are better primaries, and (b) Cyan and Magenta pigments are hard to make, requiring (relatively) modern processes.