CMYK is also called print color mode. The big difference between this and RGB is that RGB is a luminous color mode where you can still see what’s on the screen in a dark room.
CMYK is a kind of color mode that depends on reflection. Why can we read the content of newspapers? It’s when sunlight or light hits the newspaper and reflects the content back into our eyes. CMYK is visible only when there is an external light source. So you can’t read in a dark room. CMYK mode is what you see in print. For example, periodicals, magazines, newspapers, and brochures all use the CMYK model.
CMY is the initials of three printing inks: Cyan, Magenta, and Yellow. And K is the last letter of black, and K is used to avoid confusion with blue.
Theoretically, only three types of CMY ink are enough. If you add CMY together, you should get black. But high purity ink is not yet realized, CMY added result is dark red. Therefore, in order to ensure the black output, a special black ink is added to blend.
RGB is generally referred to as [color primary colors], R (red) red, G (green) green, and B (blue) blue. The color gradation of RGB is 0-255. As RGB is color light, the superposition of color is brighter and brighter, so it is also known as [additive color method]. When the value of the three colors is 255, white will appear; otherwise, when the value of the three colors in RGB is 0, it will become black. from the above RGB color relation diagram, it can be known that B+G is cyan, B+R is magenta, G+R is yellow, positive and CMYK color complementary.