Yellow as one of the primary colors, seems to be different with other primary colors. Because in the offset printing, most of the yellow ink is as the first color to printing. Therefore, yellow version of the amount of ink, order to reconcile subtle levels of representation, to master properly. After all, the first color version is the foundation. Therefore, yellow ink printing is particularly important.
Why is often cited as the first yellow color
General color print by use of the yellow ink pigment is a kind of chromate belongs to the inorganic pigment, divided into lemon yellow, weak yellow, deep yellow, orange, spectrophotometry, of 5, specific gravity is 5.6 ~ 6, with oily small, more than major, particle diameter, covering power strong characteristic. Yellow ink is often cited as the first color printing, mainly from the following points to consider:
(1) from the ink transparency and printing color of sequence in relation to, in the ordinary circumstances, shall the covering power is strong, the printing ink of poor transparency in printing behind. Due to the yellow ink covering power is strong, if put it in other ink overprint, can make prints lack luster. Such as: the first color printing ink, the second yellow color printing ink magenta, so that the printed bright red effect is very good; Conversely, red ink printing first, then ink dieyin huang, printing out red effect is very poor.
Of course, with the continuous improvement of printing ink, yellow ink in increasing transparency, with domestic offset printing light fast drying, printing ink, for example, it is more transparency, if select high-quality transparency high ink in the color overprint after time sequence, its effect also is possible. In fact, there have been many manufacturers choose the color sequence.
2. The first color printing yellow ink can have flattened some paper rough surface effect, but also because it less oil content, next to the color overprint go up.
3. From the depth of the process of intensity, light color overprint in the dark, if there is no trace overprint, also not be very conspicuous. Conversely, in deep color overprint light color, if not overprint, will be completely exposed.
So with a red edition version of yellow, appear to perceive not longitudinal trace, and with yellow version of red edition, if not overprint, it is very easy to watch out.
Printing yellow ink which should pay attention to the problem
Because a light yellow, to the human eye is not sensitive, so printing, yellow version of ink amount control of network and subtle levels of control, to print edition, red than green version much more difficult.
The following is a yellow ink printing more attention to the aspects:
1. The formal before printing, the printing plate to inspect, a method is to use 5 ~ 10 times as much a magnifying glass to identify the depth of the plate, and see whether the network and electrical points four color of the same film dot size. Usually, allow plate than electrical points of the film slightly small outlets some, if the color film score plate network node some bigger, indicates that bask in out of the plate is too deep. Check the printing plate depth, will look at whether the quality is suitable outlets.
2. Yellow ink can be roughly classified into three tonal, namely: a little with the green weak yellow ink, with a little red ink, spectrophotometry deep yellow of ink. As for the selection of the offset printing a yellow ink, according to the original manuscript of the hue to decide. In Indian yellow version, to estimate the change of ink itself, after drying of change, such as the neuter color more yellow ink dries easy to be suffused with red, etc. In the offset printing turned on, according to the sample checking process of monochromatic.
3. Printing process inspection gradation yellow version, should pay attention to the light around. For example: incandescent lamp glow is orange, fluorescent light slants a little blue purple, in such observed under the lamps and lanterns of colour occur visual deviation.
In addition, in the inspection yellow, tend to use blue glass. Because the light source of unity, easy to judge is not clear, but with blue (yellow color) glass can be avoid light source is not stable errors. Or check in yellow, wear the blue sunglasses.
4. In normal printing, should often see transfer, will prints and tear sheets careful controls. By means of the comparison of the various units of sampling and tear sheets in the same light source of the adjacent position in comparison. Had better be to be in workshop offline discern the depth of the process of natural light, such as color overprint slant. Only in this way can we ensure that prints and tear sheets of consistent process.
5. In control yellow ink ink amount, should guarantee seal with monochromatic sample interaction sample/communicate the density of reflection. Have conditions, can use color reflection density spectrometer, measurement and calculation of yellow, in order to realize digital and standardization of the technology of quality management.
If it is able to measurement, calculation process, do evidence to be in, can improve labor productivity, effectively save the raw materials, fundamentally change that by sight, with experience to control the process of size, dot enlargement of the backward quality management methods.
6. The monochromatic offset printing press in to Y, M, C, K color sequence printing, printed the yellow is the key step, have to control the yellow ink amount of ink. Yellow ink amount of ink, after the magenta, blue print, black ink will then increase the amount of ink, can appear otherwise partial color phenomenon. Such as the characters of mainly pictures, the skin is the focus of printing copy, if yellow ink amount is large, and magenta inks small amount of words, printed characters yellow color of skin, can give a person the feeling of color of skin not healthy. If the landscape is, is to reflect the natural landscape is given priority to, give priority to color blue, yellow for auxiliary tonal. Print landscape painting is very important printed the yellow, blue sky, white clouds is green version is given priority to, and green trees and flowers is yellow and green version outlets dieyin edition presented color, yellow version of large amount of ink, green version of the small amount of ink, green vegetation will be yellow.
In short, printing yellow version when must grasp good size gradation. Avoid large, ink dot enlargement, dirty version, and paste version, imprinting dry slowly, and the process of small, ink layer without burnish, network not strong, partial light FaXu, network and field not finish and no clear disadvantage.
