Color Management: Know about Color Spaces

Time:2021/03/11 09:50:42 Browse:205

Linshang Technology Co., Ltd. released two new exquisite and portable colorimeters in 2020. Linshang two color difference meters support seven color spaces: CIE Lab, Luv, LCh, Yxy, CMYK, RGB and Hex. So do you know what these seven color spaces represent? Let's introduce for you.

I. What is CIE Lab color space?

RGB color model
RGB color model

"CIE" refers to an authoritative international organization on colors, lighting, etc. The specific representative is International Commission on Illumination. Lab is composed of a luminance channel and two color channels. CIELAB color space is a device-independent, "standard observer" model. The colors it defines are not relative to any particular device such as a computer monitor or a printer, but instead relate to the CIE standard observer which is an averaging of the results of color matching experiments under laboratory conditions. (Quoted form Wikipedia). 

1. "L" represents brightness

The larger the value of L, the brighter. The smaller the darker. The range of this value is approximately 0-100. When the value is 0, it represents black and when the value is 100, it represents white. 

2. "a" stands for red and green

The value from negative to positive is the evolution from green to red. 

3. "b" stands for blue and yellow

The evolution from negative to positive is the evolution from blue to yellow.

Under normal circumstances, Lab represents real numbers. When the values of a and b are both 0, it represents gray. In the process of actual use, the range of color channel is -100~+100 or -128~127.

II. Luv color space

Luv color model
Luv color model

Luv color space is simply the brightness and chroma. For example, white is a bright color, while gray is considered a less bright white. In other words, the chromaticity of white and gray are the same, but the brightness is different. In this color space, "L" represents brightness, "U" and "V" represent chroma. The range of chroma is -100 to +100 and the range of brightness is 0 to 100.

III. What is LCh color space?

Lch color model (quoted from lea.verou.me)
Lch color model (quoted from lea.verou.me)

"CHROMA" means "C" for chromaticity. "L" stands for lightness, "C" is chroma, which is the degree of color saturation, and "h" is hue, which is the overall tendency of the color. "L", "C" and "h" are the three elements of color. Brightness is the perception of the eyes on the brightness of the light source and the object surface. Brightness not only determines the degree of illumination of the object, but also determines the reflection coefficient of the object surface.

Saturation (chroma, freshness) usually refers to the vividness of a color. From a scientific point of view, the vividness of a color depends on the single degree of light emitted by this hue. The characteristics of the hue are determined by the spectral composition of the light source and the ratio of the radiation of each wavelength reflected by the surface of the colored object to the human eye. It is the qualitative appearance that colors can show and it is the most accurate standard for distinguishing various colors. In many cases, we generally use the (L a b) color space to describe colors. If the brightness and saturation remain keep unchanged, but the hue changes. We generally use Lch to describe colors. Such as the color classification of raisins, the measurement of changes in honey color and so on.

IV. What is Yxy color space?

Yxy color space
Yxy color space

The CIE Yxy space is the space derived from the XYZ values. Y is the lightness or brightness of the color. x and y are the CIE xy chromaticity coordinates, which are two of the three values normalized by the function of all three tristimulus values X, Y and Z.

V. Knowledge you should know about CMYK color space

CMY is the first letter of the names of the three printing inks, which stand for Cyan, Magenta and Yellow respectively. And K is the last letter of black, the main purpose is to confuse it with blue.

The CMYK color space is mostly used in the printing industry as a color model that relies on reflection. For example, newspaper printing is caused by sunlight or light shining on the newspaper and then reflecting 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 model. For example, CMYK model is used in periodicals, magazines, newspapers, publicity albums, etc.

CMYK color model (mixam.com)
CMYK color model (mixam.com)

VI. RGB color space

RGB color model (quoted from hisour.com)
RGB color model (quoted from hisour.com)

The RGB color space respectively represents the three primary colors R (red), G (green) and B (blue). The color scale of RGB is 0-255. Since RGB is shade, the superposition of colors is more and 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.

VII. Hex color space

This color space is simply a shorthand for hexadecimal. In HTML&CSS, the color labeling of hexadecimal code starts with a pound sign (#), followed by 6 numbers to indicate that this color labeling method is too long to use for many designers, but it is a bit confusing. Some people don’t know how to write it just to choose a red or pink color. They still have to rely on Dreamweaver's color wheel to write it.

VIII. Portable colorimeter with seven color spaces

Friends who are interested in the specific color space knowledge can learn more about it. These color models play important roles in color measurement and color comparison. Linshang portable colorimeter is a professional instrument developed for measuring the color and color difference. Seven color models are installed in the colorimeter app. After the color measurement, we can choose to display the data of three color models. 

portable colorimeter application
portable colorimeter application

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