One of the changing factors of screen printing color

This is a basic article written for inexperienced beginners, but the content contains an important lesson that in order to obtain stable and high-quality prints in the current environment of a printing plant, standards must be established. .

The hardest part is often to answer questions that seem simple. Some beginners often ask why colors change when printing. Why is it so difficult for a printer to keep a job exactly the same as the color of another job? The only answer is to use careful process control and automatic adjustment techniques to minimize color changes. This is a suitable answer when you just started working on screen printing and know nothing about the process. However, from the point of view of an experienced production and printing worker, they may not necessarily all have a clear understanding of the reasons for the color change.

If you print a simple line job, which is monochrome printing, this time you can not consider the four-color mesh tone, this answer makes sense within a certain range. Specifically, the main factors to be considered should be the following points.

Ink mix is ​​not good

If, assuming that the pigment in the ink is properly formulated, the usual cause of the color change is the added solvent. In a well-controlled shop, the ink should be ready to be supplied to the press at any time. That is, the printer should not dispense ink. In many companies, the ink is not adjusted for use by the printer, but is left to the printer to adjust, and they add and mix the ink according to their own feelings. As a result, the pigment balance in the ink is broken. For water-based ordinary inks or UV inks, the water in the ink acts in the same manner as the solvent in the solvent ink. Adding water will thin the dried ink film and affect the color of the ink, thereby reducing the density of the color. . The reasons for such problems can be further traced. In ink warehouses, ink distributors do not use weighing devices and rely on their own judgment to add the right amount of solvent, or to mix them inappropriately at first, or to change the mixing amount of ink during printing, so that the mixed ink will Produce different colors. When this job is printed again later, this situation will get worse, unless there is a sufficient ink ratio record, it is almost impossible to reproduce a color