Equipment Frontiers: Computer Color Measurement And Color Matching To Improve Printing And Proofing Efficiency

< p > computer color matching system consists of two parts: software system and hardware system. Among them, < a href= "http://www.91se91.com/news/list.aspx Classid=101112107101" > software system < /a > color matching system software, using the theory of the basis of the theory of optical basis, which can modify the color matching of single fabric and blended fabric, establish and manage the color formula library, control the quality of production, and can intelligently adjust the formula to compensate for the interaction between the dyestuff formula dyes. The hardware system is a spectrophotometer, and its basic components are light source, separate monochromatic light and photoelectric detector. < /p >
< p > the working principle of measuring and matching is that the white light emitted by the light source is irradiated on the sample, and the reflected light is separated by three prisms or diffraction gratings, and then the reflectivity of various wavelengths is calculated. The computer color matching system calculates the chromatic value or the coordinates of the three degree color space with this reflectivity, and then calculates. < /p >
< p > in this process, first of all, the basic database of dye calibration should be established, and the chromatic environment parameters of the formula should be set up. (color matching and the evaluation of light source, spectral range and wavelength interval, CIE standard color system, dyeing process, dye combination mode and color difference tolerance of dye formula), then the standard color sample will be measured, and the dye formula will be predicted and calculated. In general, the formula obtained by the computer color matching system can only be corrected 1~2 times. < /p >
< p > < strong > making recipe file < /strong > < /p >.
< p > each base cloth should be taken from the dyed fabric in production, some of which will be stored directly into the computer after being directly measured, and the other part will be used for making basic samples. The fabric with the same texture and the same structure and the same structure should be treated as different kinds of fabrics. The dye samples for making basic samples should be as many as possible, so that when matching colors, several formulations that meet the requirements can be obtained from various dyestuffs of different hue, and the choice is large, so that satisfactory results can be obtained. In order to ensure the accuracy of color matching, dye batting tests should be done when dyes with different batch numbers are changed. Each dye should be dyed into 8 basic samples with different concentrations (for fabric weight). The range of dyeing concentration and the grade of concentration should be determined according to the actual situation. < /p >
< p > in the production of samples, attention should also be paid to the specimen being made by the same person to ensure consistency. The dyes for making a set of basic samples can not be divided into 8 times. A certain amount of dyestuff should be dyed at a time to form the dye solution. The dye solution should be diluted according to the concentration of the dye solution to obtain different concentration of dye solution. The production conditions of the basic samples should be simulated as far as possible. < a href= "http://www.91se91.com/news/list.aspx? Classid=101112107108" > dyed bath pH value < /a > type and dosage of adjuvants, time, temperature, bath ratio and post treatment conditions should be the same as mass production. For blended fabrics or yarns, the basic samples of dyeing and staining should also be obtained according to the one bath or two bath method used in bulk sample production. To do this, chemical methods should be used to strip off a component from the raw material and obtain two kinds of single component fabrics for making dyed and stained samples. < /p >
< p > before the storage of basic data, the basic samples must be measured. The basic sample generally has the following principles: as far as possible, choose the large diameter hole; the surface uneven or coarser fabric should be measured more, and the average value should be taken; the surface of a set of samples should be consistent with the direction of the grain; if it is a yarn sample, it should be wrapped around the frame in advance, and the density is uniform and the number of layers is the same. It is best to wrap 4 layers. If it is woven into cloth, the result will be more accurate. The samples of pile and blankets are added to a hole of quartz glass before the test, and the sample is pressed against the outside of the glass. Determination < /p >
< p > when using computer color measuring system to measure colors, first of all, the computer and color tester should be set and standardized unified parameters, such as D65 light source, 100 field of view, or SCE, CMC L/C=2/0.5 or 2/l, etc. Before measuring colors, black and white plates should be used to calibrate colorimeter and computer. The measured objects must be kept smooth and certain tension in the coloring hole; attention should be paid to the organization of the tested objects, the difference between the positive and negative sides, and the influence of twill and fuzzing surface; attention must be paid to the uniform condition of dyeing; if the dyeing is not leveled, it must be redone; the color sample cloth should be rotated at different angles, and the directional color should be measured. < /p >
< p > < strong > mastering < a href= "http://www.91se91.com/news/list.aspx Classid=101112107102" > color matching < /a > key points < /strong > /p >
< p > when the color difference is large, it is possible to color the system as much as possible. Generally, after adjusting the formula through computer, if the system is transferred out of the system due to chromatically changing factors, it can not synchronize with the vision. At this time, the color concentration is very small. When the spectroscopic curve does not match (color change phenomenon), if the color is close, we should pay attention to whether the system adjusts the hue and vision synchronously. If it is not synchronized, it must be adjusted by visual color matching to avoid wasting color timeliness. < /p >
< p > direct dyeing must be made by computer. The reflectance curve can be used to confirm that the dye can be dyed without color change. Pay attention to the difference between the standard sample and the surface morphology of the sample, so as to make proper concentration adjustment in advance (the smoother and brightening the surface, the lighter the color matching formula). The dyes should belong to the same category, which is conducive to dyeing with one method. Even if the same type of dyestuff is used, the dyeing properties (such as dyeing rate and color fastness) should be similar, otherwise the dyeing will not be consistent, the reproducibility will be poor or the color change will be different after wearing because of the change of dyeing conditions. The same type of dyes should be used for dyeing and dyeing. The amount of dyestuff should not be too large. The amount of dyes should be as few as possible to facilitate the control of shade. < /p >
< p > generally, it should not exceed 3 dyes in color matching. If it is possible to use one dye in the same dye, the desired color is the best. The combination of two dyes is also related to the color of the dye. For example, green light yellow (disperse yellow SE-2C) is combined with red light blue (disperse blue SE-2R), the green color is dark and dark, and it matches with pure blue (disperse turquoise blue H-G and disperse blue 2BLN). When using the basic data system (CCM) to match colors, it is best to use different material correction to avoid the difference of the color concentration predicted by the formula. When the system has color library data, it is necessary to use the color system matching as far as possible. A color library system with appropriate color stock and good rules (CCS) can greatly enhance the efficiency of color matching. After dyeing, the cloth should be dried and cooled before judging the color. < /p >
< p > there are still some shortcomings in computer color matching. For example, in the process of computer color matching, there are many factors that affect the accuracy of color matching. In practical application, the main influencing factors include dyeing process control, dye strength, pretreatment of dyed gray cloth, color measurement layer of fabric, dyeing performance of fabric, weighing error and so on. Therefore, these factors must be strictly controlled. The color matching of computer depends on the number of dyes in the database, so there are some limitations. The solution is to increase the color of the building to reduce the limitation. < /p >
< p > color matching technology as a key emerging technology in the printing and dyeing industry, has realized the color data transfer confirmation and colorless proofing between printing and dyeing enterprises and customers, effectively raised the reaction speed, effectively controlled the chromatic aberration, and fundamentally improved the efficiency of the entire printing and dyeing enterprise, and it will become the leading factor in the printing and dyeing industry. < /p >