In printing work orders, color box printing plants often have monochrome machines to print two-color and three-color things. For example, some couplets have overprinted colors, and it is not convenient to print on the four-color machine. In addition, the price of some printing sheets is very low and it is not worthwhile to print on a four-color machine, so we will consider using a single color machine for overprint.
However, it is not so easy to use a monochrome machine to overprint color. It requires the master to have a better level and the machine. Otherwise, the quality of the finished printing products is too poor. If the color printing is too bad and the customer doesn't pay, it will lose a lot.
According to the actual experience of printing color box packaging, this paper summarizes some small methods, which can be as perfect as possible when overprinting four colors with a monochrome machine. The printing industry knows that when the four-color machine is printing, because the four groups of rubber sticks work at the same time, the printing interval of each color is very short, and the ink will not be dry. It belongs to the wet stack wet printing method. Printing with a monochrome machine is different. When the first color is printed and the second color is printed, the first color is dry, so it belongs to the dry and wet printing method. Understand the difference between these two printing methods. When we use monochrome machine to overprint color, we can't use the same mode as four-color machine. The four-color printing method is: black, blue, red and yellow. We can't refer to this color sequence when printing with a monochrome machine. How to choose the color order.
In order to make the monochrome machine print the best printing effect, we generally have the following two reference methods:
1. Arrange according to lightness. That is, the dark color is printed first, and then the bright color is printed. For example, first print black and blue, and then print yellow and red.
2. Arrange according to the transparency and covering ability of the ink, such as printing blue and black first, and then printing red and yellow.
In addition, in the process of printing, we should make clear the characteristics of the sample to be printed. For example, whether there are heavy color blocks, large color blocks, or more pictures and less words in the sample, if any, we should flexibly adjust the color printing order, which needs experience to decide. Another point is that in the printing process, blue and red must be aligned, otherwise the printed products are easy to design and color. Yellow and black are relatively acceptable, and the requirements are not so high. Even if the printing of these two colors deviates a little, they will not be obvious.