One: The strength of light directly affects the judgment of the color of printing samples. The strength of light not only affects the color of light, but also changes the appearance of color.
We usually observe a light-receiving cylinder. The light-on side is the tone, and the back-light surface is the dark tone. The combination of light and dark is the midtone. The same object, under the standard light source, is a positive color. If the light gradually becomes stronger, its hue will also change to a bright hue, and the light will be enhanced to a certain degree, and any color may turn white. Black porcelain also has a white point of reflection because of the concentration of light at the point of reflection and its strong reflection. In the same way, the light gradually decreases, and the various colors change to a hue with low lightness, and the light weakens to a certain degree, and any color will turn black, because the object does not reflect any light or black. Table 1 shows the effect of light intensity on color.
The print shop's sample stand must meet the requirements. Generally, the illuminance must reach about 100 lx in order to correctly identify the color.
II: There are differences in the appearance under the shade of light and the appearance under the sunlight. In the actual production, most of them work under the illumination of the power source, and each light source has a certain color. This brings certain difficulties to the correct judgment of the original or product color. Under the shade of color, the color change is generally the same color becomes lighter and the complementary color becomes darker. For example, the red color is lower, the red is lighter, the yellow color is orange, and the green color is changed. Dark, dark green, white red. Under the green light, the green lighter, the green lighter, the yellowish greenish yellow, the reddish black, and the white green.
Under the yellow light, the yellow lightens, the magenta turns red, the green turns green, the blue turns black, and the white turns yellow.
Under the blue light, the blue lightens, the green lightens, the green darkens, the yellow turns black, and the white turns blue.
In the printing shop, fluorescent lamps with higher color temperature (3500~4100k) and better color rendering coefficient are generally selected as the sample light source, but it should be noted that fluorescent lamps are slightly blue-purple.
Three: look at the proofs first look at the printed products and look at the printed products and then look at the proofs, the results will be slightly different, two times to see a color does not feel the same. This phenomenon is called sequential color contrast reaction. See Table 2 for the changes.
Why do you have successive color contrast reactions? This is because the first look makes the color of the colored nerve fibers excited, immediately look at other colors, other color nerves quickly excited to cause a sense of color, while the color of the first look at the color of the nerve after the suppression of excitement, and then excited Slower, causing a negative hue response. This reaction adds a new color hue to create a new color, so change the look after the color. Moreover, the hue of the change is still regular, and it is the change in the complementary color of the first look.
Understand the above three issues and understand their changing patterns, we should pay attention to the actual look, so as to ensure the stability and improvement of the quality of printed products.
The color of the eye that looks at first and then looks at the change of color tends to red yellow green blue purple white
Red earth red green yellow green blue blue green Tsui
Yellow Purple Red Gray Yellow Green Blue Fresh Purple Purple Purple
Green, red, orange, gray, purple, purple, red, magenta
Blue orange golden yellow green gray blue red purple light orange
Purple Orange Lemon Yellow Yellow Green Green Blue Gray Purple Green Yellow â—Ž
Prints are divided into monochrome printing and color printing. Monochrome printing is a printing method that is limited to one color. Color printing can print full-color pictures. Most of the color printing uses color separation to reflect various hue, and the color separation is composed of red (M), yellow (Y), blue (C), and black (K) four-color screens. The hue of the color separation manuscript can be based on the principle of color separation, and the CMYK dots in the chromatogram can be directly marked with text. When special colors are required, special colors other than the four colors must be used to set spot colors. The spot color version can specify a hue in the chromatogram and is specifically tuned.
Prints are divided into monochrome printing and color printing. Monochrome printing is a printing method that is limited to one color. Color printing can print full-color pictures. Most of the color printing uses color separation to reflect various hue, and the color separation is composed of red (M), yellow (Y), blue (C), and black (K) four-color screens. The hue of the color separation manuscript can be based on the principle of color separation, and the CMYK dots in the chromatogram can be directly marked with text. When special colors are required, special colors other than the four colors must be used to set spot colors. The spot color version can specify a hue in the chromatogram and is specifically tuned. 
Printing color representation
Ink printing color, there are generally two ways:
(1) Print colors using four-color inks, mixed dots, and overlap printing.
(2) Mix the printed inks to produce a spot color, that is, use spot color printing, and express colors with solid colors or dots. The color designation and plate making methods of these two methods are all different in print design.
1. In the monochromatic printing of grayscale monochrome printing, the deepest actual level is 100%; the white level is 0%, during which different shades of grey are called from different mesh points, ie, using percentage control. For ease of reading, anti-white characters are usually applied on 50% to 100% dark gray scales, and 50% to 0% are black characters, but they should also be considered as appropriate according to the different colors.
2. Color printing four-color color printing is the use of red, yellow, blue, black four-color printing to produce ever-changing colors. It can take advantage of color separation printing. However, the color of the text or graphics desired in the design can use the color scale to look up the CMYK value of each color. However, certain special colors such as gold, bank, and fluorescent colors cannot be formed by four-color ink overprinting, and must be printed with a spot color version of spot color ink.
Color version changes
The demands of modern design are varied and varied. To express a more perfect mood or a more special effect, only the color of some image manuscripts is restored, and the required requirements cannot be achieved. Therefore, it is possible to use the color plate process to change or change the order and quantity of the color plate to achieve special color design requirements. 
1, black and white positive film to two colors
With two sets of color plates, two printings using a monochrome printer are completed, or the color printer is completed at one time. The use of two-color printing usually uses a monochrome black plate and then captures another color as the color tone of the color plate in combination printing. In the case where the original effect is not so good, this two-color printing method often produces unexpected effects. 
î—¥2, color plate replacement printing
Color plate replacement printing is the change of the color plate in the printing design. The purpose is to pursue a special picture effect, which can often bring unexpected results. In the four versions of color separation, if two or three colors are exchanged and printed, the hue of the entire original surface will change, resulting in great changes. For example, the green tree is composed of yellow, blue and a little black; if the yellow version is changed to red printing, and the blue version is unchanged, the green tree will become purple, similar to the design of certain posters and Occasional use of layout design, will get a novel effect. 
The color print is two-color printing in the four editions, and there are only two editions, namely two-color printing. A third color can be produced, such as mixing blue and yellow to get green, and getting green shades is completely dependent on the ratio of dots between blue and yellow. A normal color modulates the color picture and prints it with two different color plates to achieve a special color effect.
In the design, occasionally using this type of printing will produce a fresh feeling. Applied to the environment, atmosphere, time and seasons of the scenery can have special creative effects. 
In order to seek a special color effect, one version of the four-color printing can be pulled away and the three-color printing is retained. In order to make the picture clear and prominent, it is often the case that the color is heavy and the tone is darker in the three colors as the main color. 
It is also possible to print one of the three editions as a spot color. For example, making a black edition silver or gold produces a special color combination. Take advantage of stencil conversion techniques, handling of exaggeration, emphasis, and special effects. 
3, monochrome printing
Monochrome printing refers to the use of a version of printing, which can be black printing, color printing, or spot color printing. Spot color printing refers to a special color that is required in a special modulation design as a base color, and is completed by one printing. Monochrome printing is used more extensively and also produces rich shades that achieve satisfactory results. In monochrome printing, color paper can also be used as a background color, and the printed effect is similar to two-color printing, but it has a special flavor. Special colors Special colors include glossy color printing and fluorescent color printing.
The glossy color printing mainly refers to the printing of gold or silver. To produce spot color printing, printing is generally performed using gold ink or silver ink, or by using gold powder, silver powder, bright oil, and quick-drying agent. Under normal circumstances, it is best to print gold and silver background color, because gold or silver ink is printed directly on the surface of the paper, because the degree of oil absorption on the paper will affect the gloss of gold and silver ink. In general, a tone can be selected based on design requirements. If you want gold warm luster, you can use the red version as the background color; otherwise, you can choose blue; to be both deep and shiny, you can choose black bottom. Fluorescent color printing refers to the use of spot color printing fluorescent colors, using fluorescent ink printing, because of the different nature of the ink, the printed color is very eye-catching and bright. Used in design work, it can produce distinctive and unique effects.
We usually observe a light-receiving cylinder. The light-on side is the tone, and the back-light surface is the dark tone. The combination of light and dark is the midtone. The same object, under the standard light source, is a positive color. If the light gradually becomes stronger, its hue will also change to a bright hue, and the light will be enhanced to a certain degree, and any color may turn white. Black porcelain also has a white point of reflection because of the concentration of light at the point of reflection and its strong reflection. In the same way, the light gradually decreases, and the various colors change to a hue with low lightness, and the light weakens to a certain degree, and any color will turn black, because the object does not reflect any light or black. Table 1 shows the effect of light intensity on color.
The print shop's sample stand must meet the requirements. Generally, the illuminance must reach about 100 lx in order to correctly identify the color.
II: There are differences in the appearance under the shade of light and the appearance under the sunlight. In the actual production, most of them work under the illumination of the power source, and each light source has a certain color. This brings certain difficulties to the correct judgment of the original or product color. Under the shade of color, the color change is generally the same color becomes lighter and the complementary color becomes darker. For example, the red color is lower, the red is lighter, the yellow color is orange, and the green color is changed. Dark, dark green, white red. Under the green light, the green lighter, the green lighter, the yellowish greenish yellow, the reddish black, and the white green.
Under the yellow light, the yellow lightens, the magenta turns red, the green turns green, the blue turns black, and the white turns yellow.
Under the blue light, the blue lightens, the green lightens, the green darkens, the yellow turns black, and the white turns blue.
In the printing shop, fluorescent lamps with higher color temperature (3500~4100k) and better color rendering coefficient are generally selected as the sample light source, but it should be noted that fluorescent lamps are slightly blue-purple.
Three: look at the proofs first look at the printed products and look at the printed products and then look at the proofs, the results will be slightly different, two times to see a color does not feel the same. This phenomenon is called sequential color contrast reaction. See Table 2 for the changes.
Why do you have successive color contrast reactions? This is because the first look makes the color of the colored nerve fibers excited, immediately look at other colors, other color nerves quickly excited to cause a sense of color, while the color of the first look at the color of the nerve after the suppression of excitement, and then excited Slower, causing a negative hue response. This reaction adds a new color hue to create a new color, so change the look after the color. Moreover, the hue of the change is still regular, and it is the change in the complementary color of the first look.
Understand the above three issues and understand their changing patterns, we should pay attention to the actual look, so as to ensure the stability and improvement of the quality of printed products.
The color of the eye that looks at first and then looks at the change of color tends to red yellow green blue purple white
Red earth red green yellow green blue blue green Tsui
Yellow Purple Red Gray Yellow Green Blue Fresh Purple Purple Purple
Green, red, orange, gray, purple, purple, red, magenta
Blue orange golden yellow green gray blue red purple light orange
Purple Orange Lemon Yellow Yellow Green Green Blue Gray Purple Green Yellow â—Ž
Prints are divided into monochrome printing and color printing. Monochrome printing is a printing method that is limited to one color. Color printing can print full-color pictures. Most of the color printing uses color separation to reflect various hue, and the color separation is composed of red (M), yellow (Y), blue (C), and black (K) four-color screens. The hue of the color separation manuscript can be based on the principle of color separation, and the CMYK dots in the chromatogram can be directly marked with text. When special colors are required, special colors other than the four colors must be used to set spot colors. The spot color version can specify a hue in the chromatogram and is specifically tuned.
Prints are divided into monochrome printing and color printing. Monochrome printing is a printing method that is limited to one color. Color printing can print full-color pictures. Most of the color printing uses color separation to reflect various hue, and the color separation is composed of red (M), yellow (Y), blue (C), and black (K) four-color screens. The hue of the color separation manuscript can be based on the principle of color separation, and the CMYK dots in the chromatogram can be directly marked with text. When special colors are required, special colors other than the four colors must be used to set spot colors. The spot color version can specify a hue in the chromatogram and is specifically tuned. 
Printing color representation
Ink printing color, there are generally two ways:
(1) Print colors using four-color inks, mixed dots, and overlap printing.
(2) Mix the printed inks to produce a spot color, that is, use spot color printing, and express colors with solid colors or dots. The color designation and plate making methods of these two methods are all different in print design.
1. In the monochromatic printing of grayscale monochrome printing, the deepest actual level is 100%; the white level is 0%, during which different shades of grey are called from different mesh points, ie, using percentage control. For ease of reading, anti-white characters are usually applied on 50% to 100% dark gray scales, and 50% to 0% are black characters, but they should also be considered as appropriate according to the different colors.
2. Color printing four-color color printing is the use of red, yellow, blue, black four-color printing to produce ever-changing colors. It can take advantage of color separation printing. However, the color of the text or graphics desired in the design can use the color scale to look up the CMYK value of each color. However, certain special colors such as gold, bank, and fluorescent colors cannot be formed by four-color ink overprinting, and must be printed with a spot color version of spot color ink.
Color version changes
The demands of modern design are varied and varied. To express a more perfect mood or a more special effect, only the color of some image manuscripts is restored, and the required requirements cannot be achieved. Therefore, it is possible to use the color plate process to change or change the order and quantity of the color plate to achieve special color design requirements. 
1, black and white positive film to two colors
With two sets of color plates, two printings using a monochrome printer are completed, or the color printer is completed at one time. The use of two-color printing usually uses a monochrome black plate and then captures another color as the color tone of the color plate in combination printing. In the case where the original effect is not so good, this two-color printing method often produces unexpected effects. 
î—¥2, color plate replacement printing
Color plate replacement printing is the change of the color plate in the printing design. The purpose is to pursue a special picture effect, which can often bring unexpected results. In the four versions of color separation, if two or three colors are exchanged and printed, the hue of the entire original surface will change, resulting in great changes. For example, the green tree is composed of yellow, blue and a little black; if the yellow version is changed to red printing, and the blue version is unchanged, the green tree will become purple, similar to the design of certain posters and Occasional use of layout design, will get a novel effect. 
The color print is two-color printing in the four editions, and there are only two editions, namely two-color printing. A third color can be produced, such as mixing blue and yellow to get green, and getting green shades is completely dependent on the ratio of dots between blue and yellow. A normal color modulates the color picture and prints it with two different color plates to achieve a special color effect.
In the design, occasionally using this type of printing will produce a fresh feeling. Applied to the environment, atmosphere, time and seasons of the scenery can have special creative effects. 
In order to seek a special color effect, one version of the four-color printing can be pulled away and the three-color printing is retained. In order to make the picture clear and prominent, it is often the case that the color is heavy and the tone is darker in the three colors as the main color. 
It is also possible to print one of the three editions as a spot color. For example, making a black edition silver or gold produces a special color combination. Take advantage of stencil conversion techniques, handling of exaggeration, emphasis, and special effects. 
3, monochrome printing
Monochrome printing refers to the use of a version of printing, which can be black printing, color printing, or spot color printing. Spot color printing refers to a special color that is required in a special modulation design as a base color, and is completed by one printing. Monochrome printing is used more extensively and also produces rich shades that achieve satisfactory results. In monochrome printing, color paper can also be used as a background color, and the printed effect is similar to two-color printing, but it has a special flavor. Special colors Special colors include glossy color printing and fluorescent color printing.
The glossy color printing mainly refers to the printing of gold or silver. To produce spot color printing, printing is generally performed using gold ink or silver ink, or by using gold powder, silver powder, bright oil, and quick-drying agent. Under normal circumstances, it is best to print gold and silver background color, because gold or silver ink is printed directly on the surface of the paper, because the degree of oil absorption on the paper will affect the gloss of gold and silver ink. In general, a tone can be selected based on design requirements. If you want gold warm luster, you can use the red version as the background color; otherwise, you can choose blue; to be both deep and shiny, you can choose black bottom. Fluorescent color printing refers to the use of spot color printing fluorescent colors, using fluorescent ink printing, because of the different nature of the ink, the printed color is very eye-catching and bright. Used in design work, it can produce distinctive and unique effects.