= The difference between RGB and CMYK and what is a spot color =

01. What is RGB?

RGB is based on a black medium, and various colors are obtained by superimposing the brightness of the three primary colors of the light source (red, green, and blue) in different proportions.

In human words, as long as the output is an electronic screen, then the RGB mode needs to be used.

02. What is CMY?

CMY is based on a white medium. By printing inks of different proportions of the three primary colors (cyan, magenta, and yellow), it absorbs the corresponding wavelengths in the original color light, so as to obtain various color reflection effects.

In human words, as long as the output is not an electronic screen, then the CMYK mode needs to be used.

Isn't it very strange, what is the difference between CMY and CMYK, in fact, in theory, CMY can call out K (black), but people find that K (black) is used a lot in practice, if you often need to use it To call out K (black) from CMY, one will waste ink, and the other will be inaccurate, especially for small characters, even now it cannot be completely registered. The third is to use 3 kinds of ink for printing, which is not easy to dry, so people have introduced K (black).

03. What is a spot color?

The explanation of spot color in the Baidu Encyclopedia means: that when printing, it is not synthesized by printing C, M, Y, and K four colors, but a specific ink is used to print the color.

As I understand it, a spot color is a color specially designed for a certain printed matter. A spot color can be any color in the world, including C, M, Y, and K. It can also be regarded as one of the spot colors. The colors used for modulation can be red, orange, yellow, green, cyan, blue, purple, white, and so on.

But since there are countless colors in the world, how do I let the other party know what color I want?

At this time, there is a color standard company: PANTONE (Pantone).

PANTONE (Pantone) lists a small number of countless colors, labels these colors with color numbers, and distributes them all over the world so that even customers on the other side of the ocean tell you that the color I need is PANTONE179C, then you Looking at the color card book, you know that this color is smooth and close to Armani 405 Rotten Tomatoes.

So now PANTONE color is almost synonymous with spot color. But please don't mess with the relationship.

Since printing can theoretically have countless colors, why do so many printing houses and predecessors tell you that many colors cannot be printed?

First: the number of colors

Everyone knows that the RGB value is in the range of 0~255, that is to say, there are 256 levels, and there are three RGB colors in total, so in theory, the total number of RGB colors is 256³=16,777,216 kinds.

The CMYK value is in the range of 0~100, there are only 101 levels, and there are only three CMY colors in total, plus a special K, so in theory, the total number of CMY colors is 101³+101=1,030,402 kinds.

16,777,216 is more than 16 times the difference from 1,030,402.

Second: Price

You can use spot color inks to print the color you want. Printing with spot color inks will cost more than printing with CMYK inks, which requires a trade-off.