The hottest technical principle on color quantizat

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On the technical principles of color quantification in high fidelity printing

at the initial stage of studying high fidelity color printing technology, experts had a heated debate on the possibility of forming neutral gray with high fidelity primary color inks with more than three primary colors of CMY and the difficulty of control in practical application, and had great doubts about whether there would be collision in high fidelity multicolor printing with amplitude modulation. With the production of experimental samples and the understanding of relevant theories, these have now become standard technical specifications

at present, one of the outstanding problems is the feasibility of expressing printing color in RGB mode. The printing instrument will record the maximum force value and elongation of the specimen breaking or the force value and deformation curve during the stretching process. The brush boundary habitually regards RGB parameters as related to the equipment, and believes that the color represented by RGB parameters cannot be determined if it is separated from the specific equipment. Therefore, it is concluded that RGB parameters cannot be used to represent the printing color space. Whether RGB parameters can be used like CIELAB and other chromaticity parameters, or under what conditions RGB parameters can be used as chromaticity parameters, and clarifying these issues become the key to resolving the mystery

rgb color mode is to add and mix three primary colors to produce different colors. Its color space diagram is as follows:

the CIE RGB spectral tristimulus value introduced by the International Commission on illumination (CIE) first determines the wavelength and amount of light of the three primary colors, and then the isoenergetic spectral color of each wavelength in the visible spectral color can be expressed by a certain amount of RGB values, including the negative number of tristimulus values. These values are called spectral tristimulus values, and all spectral tristimulus values are called "standard chromaticity observer". As shown in the figure below:

this experimental method and data are the quantitative basis of modern CIE standard colorimetry system, and also the original basis of color calibration, color measurement and calculation in industry. In order to eliminate the inconvenience of using negative numbers, CIE later adopted the hypothetical XYZ trichromatic method to establish a new chromaticity map, standardized the values of the trichromatic quantities of the matched isoenergetic spectrum, and called this method and data CIE 1931 standard colorimetric system, namely 1931 CIE XYZ system. CIE XYZ chromaticity coordinates are shown in the following figure:

the relationship between RGB color mode and chromaticity can be divided into two forms. One is photoelectric conversion equipment such as scanners and digital cameras. The chromaticity value corresponding to the generated RGB color 7. The unprocessed surface of the cutting parts and accessories of the testing machine 1 should be primed and painted. Generally, 4. We can find that the fatigue testing machine is indirect when it needs line connection, that is, it is determined by the performance of the color filter or CCD device. The correspondence was not directly expressed in the early image electronic files. The other is the image processing software represented by Photoshop. In recent years, the function of color RGB value and chroma space selection has been added. Image electronic files can carry profile parameter tables that conform to ICC standards. The main function of the parameter table is to describe the corresponding relationship between color space and chromaticity of image colors. Under this condition, any color expressed in RGB can be converted to CIE XYZ color tristimulus by matrix operation. Therefore, for each RGB color value, the corresponding CIE LAB chromaticity value can be obtained. In this sense, RGB parameters have chromaticity uniqueness and can be regarded as chromaticity parameters. RGB has developed from being related to equipment in the traditional sense to being related to the profile parameter table. RGB mode can be more widely used in the printing field, including the expression of printing colors such as primary color inks

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