Иш кетма-кетлиги

Figure 13.2. Sample color gamut form 
 
Work order. Measurements are made on a test image with areas of primary colors and 
two-color overlap (yellow, orange, red, red, green, and blue areas). In addition, the test 
image should have yellow, magenta, magenta, and gray scales, memorable body 
colors, and an image that allows visual identification of printing process defects. In 
addition, the test should have a legacy to determine the possible ability. The test must 
be printed in the digital printing method under study and in the offset printing method. 
Because the copy obtained in one of the digital technologies is compared with the 
offset copy. 
The work is done in the following order. 
1. Determination of color gamut. With the help of a spectrophotometer - colorimeter, 
yellow, orange, red, green, blue and red plates are placed in the coordinate system a*, 
b*. The resulting points are connected by straight lines until a six-point color gamut 
shape is formed. Form construction is constructed for all comparable printing methods, 
such as electrophotographic and offset copies. 
2. Determining the color balance by gray. "Pseudo-gray" scale (gray scale printed on 
colored inks) is measured by area filters. Measurements are made in three areas: 
highlights, shadows, and midtones. Histograms of changes in field optical densities are 
also constructed. The difference from neutral-gray color is analyzed. For this color, the 
same optical densities are characteristic in all three areas of the spectrum. 
3. Color coordinates L*a*b* are measured on thirty-four remembered and body colors 
on the original and two copies obtained by different methods of digital printing. The 
color difference is determined by the formula ∆E=[(∆L*)2+(∆A*)2+(∆B*)2]1/2. 
Copies must have identical test images. 
Area densities of yellow, red and yellow plates are measured and a histogram of 

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printing inks is constructed. 
2. Additional measurements can be carried out according to the teacher's 
assignment. 
- In the coordinates Dot (Dor) or Sot (Sor) a process gradation curve line is 
constructed on a gray scale, where D is the optical density, S is the relative area of the 
raster element; 
- The possible capacity of the process and the minimum size of the generated 
font are determined.