Yellow as one of the three primary colors seems to be different from Other primary colors. Because in offset printing, most yellow ink is printed as the first color. For this reason, the yellow edition's ink volume, tone and subtle levels of reproduction must be mastered properly. After all, the first color version is the foundation. Therefore, the printing of yellow ink is particularly important.
First, why yellow is often used as the first color of the general color prints used in the yellow ink pigment is an inorganic pigment belonging to the chromium salt, divided into lemon yellow, light yellow, yellow, dark yellow, orange and other 5 kinds, the proportion of 5.6 ~ 6, with a small oil, specific gravity, coarse particles, strong hiding power characteristics. Yellow ink is often printed as the first color, mainly due to the following considerations.
1, from the relationship between ink transparency and printing color sequence, under normal circumstances, should be poor hiding power that is the transparency of the ink on the back printing.
Due to the strong hiding power of yellow ink, if it is overprinted on other inks, the printed matter will lack luster. Such as: the first color printing yellow ink, the second color printing products red ink, so that the printed red effect is very good; the other hand, the first printing of red ink, and then overprinted yellow ink, the red effect of printing out is very poor. Of course, with the continuous improvement of printing inks, the transparency of yellow inks is also increasing. Taking domestic offset bright-drying inks as an example, its transparency is better, if high-quality, high-transparency inks are used for overprinting. Color sequence, its effect is also possible. In fact, many manufacturers have chosen this color sequence.
2, the first color printing yellow ink can play a role in filling a rough surface of the paper, and because it contains less oil, the next color ink is easy to overprint.
3. From the point of view of the depth of the ink, the dark color is overprinted on the light color. If there is a trace of misprint, it is not very conspicuous. Conversely, printing light colors on dark colors will be exposed if overprinting is not allowed. Therefore, when the red version is overlaid with a yellow version, a slight amount of overprinting is not perceptible, and when a yellow version is used to overprint the red version, it is easy to observe if overprinting is not allowed.
Second, when printing yellow ink should pay attention to what issues should be due to yellow lighter, the human eye is not sensitive to it, so when printing, the mastery of the size of the yellow version of the ink and the control of the network subtle level, than the red version, Qing version difficult many.
The following are some aspects that require extra attention when printing yellow ink:
1, before the official printing, the plate should be checked, the method is to use 5 to 10 times the magnifying glass to identify the depth of the printing plate, see whether its outlets and electricity divided four-Color Film outlets the same size. Usually, the plate is allowed to be slightly smaller than the dot of the electro-divided film. If the dot of the plate of the printing plate is larger than the dot of the color film, the printing plate is too dark. After checking the depth of the plate, we must also look at the quality of the outlets.
2, yellow ink can be roughly divided into three colors, namely: slightly cyan pale yellow ink, yellow ink, reddish dark yellow ink. As for the type of yellow ink used in offset printing, it should be determined according to the hue of the original. In the printing of the yellow version, it is necessary to estimate the change of the ink itself, and the change after drying, such as yellow ink after the neutral color is dry, is likely to be reddish. When the offset is turned on, proofread the ink in a monochromatic pattern.
3. When checking the yellow ink in the printing process, pay attention to the surrounding light. For example: The incandescent light is orange and yellow, and the fluorescent light is slightly blue-violet. Observing the color under such lamps may cause a visual deviation. In addition, blue glass is often used when checking yellow. Because the light source is not uniform, it is easy to judge, but the blue (yellow complementary color) glass can avoid the error caused by the instability of the light source. Or wear blue sunglasses when checking yellow.
4. During normal printing, you should always look at the printed sheets and carefully compare the prints with the proof sheets. The method of comparison is to compare the samples and proofs of prints at the adjacent positions of the same light source. It is best to discern the darkness of the ink and the problem of overprinting in the shop under natural light. Only in this way can we ensure that the prints are consistent with the proof inks.
5. When controlling the amount of yellow ink, it should be ensured that the printed sample meets the reflection density of the monochromatic proof. Under conditional conditions, color reflectance densitometers can be used to measure and calculate the yellow color to achieve data and standardized technical quality management. If we can measure and calculate the ink color well, and do so, we will be able to increase labor productivity, effectively save raw materials, and fundamentally change the kind of backward quality management that depends on the visual and empirical control of ink size and network expansion. method.
6. When a monochrome offset press prints in the Y, M, C, and K color sequence, printing yellow is the key first step. It is necessary to control the amount of yellow ink. Yellow ink has a large amount of ink. After printing, the magenta, cyan, and black inks must be increased. Otherwise, color cast will occur. For people-oriented screens, people's skin color is the focus of printing and copying. If there is a large amount of yellow ink and a small amount of magenta ink, the yellow color of the printed characters will give people an unhealthy complexion. If it is a landscape painting, it mainly reflects natural scenery, cyan is the main tone, and yellow is the auxiliary tone. It is very important to print landscapes with yellow prints. The blue sky and white clouds are based on the green version, while the green flowers and trees are the colors that the yellow and blue versions of the dots are overprinted. The yellow version has a large amount of ink and the cyan version has a small amount of ink. The green vegetation will be yellowish.
In short, you should master the ink size when printing the yellow version. Avoid ink color, dot network expansion, dirty version, paste version, imprinting dry slowly, ink is small, ink layer is dull, dot is not strong, pale hair is weak, outlets and the field is not clean, unclear and other drawbacks.
First, why yellow is often used as the first color of the general color prints used in the yellow ink pigment is an inorganic pigment belonging to the chromium salt, divided into lemon yellow, light yellow, yellow, dark yellow, orange and other 5 kinds, the proportion of 5.6 ~ 6, with a small oil, specific gravity, coarse particles, strong hiding power characteristics. Yellow ink is often printed as the first color, mainly due to the following considerations.
1, from the relationship between ink transparency and printing color sequence, under normal circumstances, should be poor hiding power that is the transparency of the ink on the back printing.
Due to the strong hiding power of yellow ink, if it is overprinted on other inks, the printed matter will lack luster. Such as: the first color printing yellow ink, the second color printing products red ink, so that the printed red effect is very good; the other hand, the first printing of red ink, and then overprinted yellow ink, the red effect of printing out is very poor. Of course, with the continuous improvement of printing inks, the transparency of yellow inks is also increasing. Taking domestic offset bright-drying inks as an example, its transparency is better, if high-quality, high-transparency inks are used for overprinting. Color sequence, its effect is also possible. In fact, many manufacturers have chosen this color sequence.
2, the first color printing yellow ink can play a role in filling a rough surface of the paper, and because it contains less oil, the next color ink is easy to overprint.
3. From the point of view of the depth of the ink, the dark color is overprinted on the light color. If there is a trace of misprint, it is not very conspicuous. Conversely, printing light colors on dark colors will be exposed if overprinting is not allowed. Therefore, when the red version is overlaid with a yellow version, a slight amount of overprinting is not perceptible, and when a yellow version is used to overprint the red version, it is easy to observe if overprinting is not allowed.
Second, when printing yellow ink should pay attention to what issues should be due to yellow lighter, the human eye is not sensitive to it, so when printing, the mastery of the size of the yellow version of the ink and the control of the network subtle level, than the red version, Qing version difficult many.
The following are some aspects that require extra attention when printing yellow ink:
1, before the official printing, the plate should be checked, the method is to use 5 to 10 times the magnifying glass to identify the depth of the printing plate, see whether its outlets and electricity divided four-Color Film outlets the same size. Usually, the plate is allowed to be slightly smaller than the dot of the electro-divided film. If the dot of the plate of the printing plate is larger than the dot of the color film, the printing plate is too dark. After checking the depth of the plate, we must also look at the quality of the outlets.
2, yellow ink can be roughly divided into three colors, namely: slightly cyan pale yellow ink, yellow ink, reddish dark yellow ink. As for the type of yellow ink used in offset printing, it should be determined according to the hue of the original. In the printing of the yellow version, it is necessary to estimate the change of the ink itself, and the change after drying, such as yellow ink after the neutral color is dry, is likely to be reddish. When the offset is turned on, proofread the ink in a monochromatic pattern.
3. When checking the yellow ink in the printing process, pay attention to the surrounding light. For example: The incandescent light is orange and yellow, and the fluorescent light is slightly blue-violet. Observing the color under such lamps may cause a visual deviation. In addition, blue glass is often used when checking yellow. Because the light source is not uniform, it is easy to judge, but the blue (yellow complementary color) glass can avoid the error caused by the instability of the light source. Or wear blue sunglasses when checking yellow.
4. During normal printing, you should always look at the printed sheets and carefully compare the prints with the proof sheets. The method of comparison is to compare the samples and proofs of prints at the adjacent positions of the same light source. It is best to discern the darkness of the ink and the problem of overprinting in the shop under natural light. Only in this way can we ensure that the prints are consistent with the proof inks.
5. When controlling the amount of yellow ink, it should be ensured that the printed sample meets the reflection density of the monochromatic proof. Under conditional conditions, color reflectance densitometers can be used to measure and calculate the yellow color to achieve data and standardized technical quality management. If we can measure and calculate the ink color well, and do so, we will be able to increase labor productivity, effectively save raw materials, and fundamentally change the kind of backward quality management that depends on the visual and empirical control of ink size and network expansion. method.
6. When a monochrome offset press prints in the Y, M, C, and K color sequence, printing yellow is the key first step. It is necessary to control the amount of yellow ink. Yellow ink has a large amount of ink. After printing, the magenta, cyan, and black inks must be increased. Otherwise, color cast will occur. For people-oriented screens, people's skin color is the focus of printing and copying. If there is a large amount of yellow ink and a small amount of magenta ink, the yellow color of the printed characters will give people an unhealthy complexion. If it is a landscape painting, it mainly reflects natural scenery, cyan is the main tone, and yellow is the auxiliary tone. It is very important to print landscapes with yellow prints. The blue sky and white clouds are based on the green version, while the green flowers and trees are the colors that the yellow and blue versions of the dots are overprinted. The yellow version has a large amount of ink and the cyan version has a small amount of ink. The green vegetation will be yellowish.
In short, you should master the ink size when printing the yellow version. Avoid ink color, dot network expansion, dirty version, paste version, imprinting dry slowly, ink is small, ink layer is dull, dot is not strong, pale hair is weak, outlets and the field is not clean, unclear and other drawbacks.
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