CMYK is also called the printing color mode. The biggest difference between it and RGB is that RGB mode is a luminous color mode, and you can still see the content on the screen in a dark room.


CMYK is a color mode that relies on reflections. Why can we read the content of newspapers? It is because the sunlight or light shines on the newspaper, and then reflects the content into our eyes. CMYK can only be seen when there is an external light source. So it is impossible to read in a dark room. As long as the image seen on the printed matter is expressed in CMYK mode. For example, periodicals, magazines, newspapers, publicity albums, etc., all use the CMYK model.

CMY is the initial letter of the names 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 speaking, only three kinds of inks of CMY are enough, and CMY should be added together to get black. But high-purity ink cannot be realized for the time being, and the result of CMY addition is dark red. Therefore, in order to ensure the black output, it is necessary to add a special black ink to blend.


RGB is generally called [the three primary colors of color light], R (red) red, G (green) green, and B (blue) blue. The color scale of RGB is 0-255. Since RGB is color light, the superposition of colors is more and more The brighter, so it is also called [additive color method]. When the values of the three colors are 255, white will appear. On the contrary, when the values of the three colors of RGB are all 0, it will become black. From the RGB color relationship diagram in the figure above, we can see that B+G is cyan, B+R is magenta, and G+R is yellow, which is complementary to CMYK colors.

What happens if RGB is used for printing?

RGB CMYK color look like