@rgb > LAB is visible range visible to the 👁‍
Basically... This model is made for that purpose. But made by scientists for computers, shall we say. It's easy to calculate but unintuitive. There are at least a few others that will also separate luminance from color and fit into 3 coordinates.

> I knew that rgb is light, and cmyk is just added black
Light is primarily an electromagnetic wave. We can CREATE the sensation of a particular color with 3 LEDs, but it won't be the same as a wave.

We can create the same sensation by using other LEDs or even light reflected from paper. In the CMYK model, no paint is white, and each paint is BLOCKING one of the primary colors.