There are so many color difference instruments on the market, and there are many indicators for measuring color. It is easy to be confused and don't understand the meaning. This article mainly introduces the meaning of color indicators of color difference instrument. The purpose of color spectrum color difference instrument has always been to make friends with color and make the color true and unified. In that case, we should do two things. First, how to define color and how to quantify color. Second, how to manage color.
Today, let's talk about the definition and quantification of color.
Color space: RGB
As early as 1704, Newton proposed that the essence of color is light; In 1854, Glassman summarized Glassman's color mixing law; Then in 1855, Maxwell proposed that red, green and blue could be mixed to produce colors of various hues.
So can red, green and blue match all the colors?
This question depends on "whether all colors can be divided into a combination of red, yellow and blue". That is, can the addition of red, yellow and blue light produce all the colors that human beings can perceive?
Then the scientists began various experiments and finally found that the answer was: Yes, but neither.

Experiment on "chromaticity characteristics of spectral color"

After the spectrum of a specific color is obtained through the test, we can know the intensity value of each wavelength of the color and the intensity value of its equivalent trichromatic light (RGB).
In this way, there is the matching ratio of RGB trichromatic light equivalent to this specific spectrum. This matching ratio can be used to roughly quantify color. The matching ratio after normalization is the so-called chromaticity coordinate.

In this way, all colors that can be distinguished by human eyes in nature. As long as you can distinguish the color, you can quantify it in this way. Although the color can also be described (uniquely) by spectral curve, but! Very intuitive, from 780nm to 380nm! Such naming is unrealistic. Therefore, not all colors can be divided into a combination of red, yellow and blue.

RGB color space

Color space: XYZ
However, if it is named after the matching value of RGB, only three data are needed (after normalization, only two data are needed). It took mankind 300 years to get to this point. On this basis, a mathematical coordinate transformation is carried out (the coordinates are changed from RGB to XYZ)

Tristimulus value

This is the CIE 1931 XYZ chromaticity diagram we usually see.
Of course, in this way, the "lightness" information contained in the three stimulus values is completely lost, leaving only the information of relative ratio. Therefore, CIE 1931 XYZ chromaticity diagram can only see the information of chromaticity (hue and saturation), but not lightness.
Color space: Munsell
In 1905, the American painter Munsell summarized the experience and research results of color scientists over the past two centuries and put forward the Munsell color system.

Munsell color space

Munsell color classification method is a pure psychological color classification method. Its three-dimensional space represents three basic visual parameters of color, namely lightness, hue and saturation.

Munsell color card

As the physical color sample of Munsell color system, Munsell atlas has been widely used in various color related industrial production and color scientific research, such as textile, dye, coating, ink, medicine, chemistry, photography, color TV and so on.
Color space: CIE LAB and CIE luv
In order to measure and evaluate the color difference more objectively and accurately, CIE formally proposed two improved uniform color spaces in 1976, namely cie1976l * u * V color space and cie1976l * a * B color space. The two values can be converted to each other. In particular, cie1976l * a * B color space was a good color space at that time, which has been widely used.

Cie1976l * a * B color space

L indicates light and dark, + is light and - is dark; A is red and green, + is red and - is green; B stands for yellow and blue, + is yellow and - is blue
Color space: LCH, CMYK, etc
Now there are many color spaces in different industries. For example: LCH, CMYK, huntelab, etc.

Cie1976l * c * h color space

L is the brightness value, C is the color saturation, and H is the hue angle.
The color difference instrument of color spectrum technology can meet the above color space to define and quantify color, so as to achieve the purpose of color management. Welcome to contact us for more information about color difference meter.