Preparation of spot color ink for short printing and application of residual ink

In packaging printing, there are many short editions with a print run of several thousand to 10000 copies, and a considerable portion of them are printed on site. When mixing spot ink, mixing too much results in waste; If there is a lack of adjustment, it is necessary to make up for it, which not only takes time, but also makes it difficult to ensure the consistency of the ink color before and after adjustment, resulting in color deviation. Therefore, it is crucial to accurately control the blending amount of spot color ink.
Determine the ink adjustment amount based on the print run
Based on years of experience, I have developed an empirical formula for controlling the amount of ink adjustment, which can help ink adjusters accurately grasp the amount of ink adjustment and provide a basis for material cost management for management personnel. 1kg of ink ≈ 1 full page solid ink volume of the paper (positive split)
When it comes to other types of paper with different openings and solid blocks of different areas, the conversion can be based on the specific situation of the print according to the above formula. Note that when mixing ink, the amount of ink mixed should be 0.5kg more than the calculated result (such as printing plates, 1kg of ink can print approximately 16 liters of large double-sided paper).
Residual ink treatment of ink
For the residual ink treatment of spot color ink used in short form on-site printing, many manufacturers currently place it for a long time, resulting in skin and dust accumulation over time, and even oxidation and deterioration, until it is scrapped. Actually, we can adopt the following two methods to deal with it.
One is to blend another batch of dark solid spot ink with the original spot ink based on its composition and color difference, but without changing the color of the blended ink.
The second is to mix and adjust the residual ink (commonly known as mixed ink) of various colors stored for a long time into "black" ink according to the coloring principle of the three primary colors of ink pigments. If the blackness is not enough, you can add the original black ink appropriately. The "black" ink produced in this way can be used for book printing and general copperplate paper color printing. As is well known, in four-color printing, the black plate only plays a skeleton role of "outlining" and "emphasizing" the middle and dark parts of the pattern, and does not affect the basic color of the pattern. However, due to the large amount of "mixed ink" ink skin, it will bring spots to the solid block areas during the printing process, and the limited blackness of "mixed ink" will make the solid block areas appear gray, so it cannot be used to print black solid block patterns.