Causes Of Color Difference In Printing Pantone Spot Color Inks
In order to improve the design and quality level of printed materials, printing plants often use spot color inks when printing trademarks, packaging, and promotional materials. This can ensure the color consistency of printing samples and meet the requirements of customers. Next, we will discuss the causes of color difference of spot color ink.
1.Ink thickness and ink balance
The control of ink hue is mainly realized by controlling the thickness of ink layer. When the thickness of ink layer changes about 0.1 μ m, the color difference of △ e = 1.5-4.5nbs will be caused, which is obviously a great influence. The ink color reproduction of offset printing is closely related to the balance of water and ink. Under the same amount of ink, large amount of water will affect the color depth. It is very important to master the balance of ink and water, especially the pH value of foutain solution. The principle of water consumption is to use as little water supply as possible under the condition of no dirty.
2.Printing pressure
The size of printing pressure has a great impact on the degree of transfer of ink from the plate to the paper. When the printing pressure is insufficient, the transfer of ink is not enough, which is not suitable for printing. When the printing pressure is too high, because the ink on the printing plate spreads to the blank part outside the picture and text, the ink transfer rate can not be improved, but also brings other disadvantages, which is not suitable for printing. Only in the appropriate printing pressure range, can the ink layer be thick, clear image, rich tone and good color reproduction.
Printing speed
With the increase of printing speed, the contact time between printing surfaces will be shortened, the dot will become virtual, the ink transfer rate will be reduced, and the printing quality will be reduced. In order to ensure the full contact of the printing surface and improve the printing quality, it is required to control the printing speed under a certain printing pressure to obtain a stable ink layer thickness.
Printing materials
01 paper whiteness
The factors affecting the whiteness of paper are as follows:
① Brightness: the most important factor.
② Dye: select dye, should be in the main wavelength near the measurement of whiteness, do not affect its reflectivity, that is, does not affect the brightness of the paper.
③ Filler: depending on its type and grade.
④ Coating: the whiteness of coated printing paper is determined by base paper whiteness, coating whiteness and coating amount.
Different whiteness and paper with certain color (such as some paper is blue or yellow) have different effects on the color of printing ink layer. Therefore, in order to reduce the influence of paper whiteness on printing color, the paper with the same whiteness should be selected in actual production.
02 smoothness and gloss of paper
There is a direct relationship between the glossiness and the inking efficiency of paper. The paper with high glossiness can get higher printing density than the paper with low glossiness at the same ink film thickness. Therefore, there is a close correlation between the gloss of printed matter and the luster of paper itself.
