Those Factors Will Interfere With The Color Of UV Offset Ink

1. Paper whiteness:

The whiteness of the paper has different effects on the color rendering of the printing ink layer. If the whiteness of the same type of white paper is different, the color difference of the printing ink layer will be reflected in the black ink composition of the offset printing ink, especially the color with a lightness value higher than 70 has a great influence, resulting in a big difference in the ratio of offset printing ink. Therefore, in actual production, the paper with the same whiteness should be selected as much as possible to reduce the influence of paper whiteness on the printing color of offset ink.

2. Paper absorbability of ink:

Under the same conditions, offset printing inks will show different printing gloss when printed on paper with different absorption properties. The structure of the paper determines that the surface of the paper has unevenness and pores formed by plant fibers. In order to obtain a good uniformity and smoothness on the paper surface, it is generally necessary to coat different thicknesses of paint on the surface of the paper. The nature and thickness of the coating determine the absorption capacity of the offset ink on the paper surface. The different absorption capacity will inevitably make the color of the printing ink layer different.

3. Paper gloss and smoothness:

The gloss of printed matter is affected by factors such as the gloss and smoothness of the paper. Printing paper is a semi-gloss surface, especially coated paper. On color prints, when 45% of the light is incident on the surface of the paper, about 4% of the light will be reflected off. This is the big noise on the surface of the first layer. The rest of the incident light will enter the offset ink layer and be selectively absorbed by the ink. Then, it is reflected through the ink layer, absorbed by the human eye, and perceived by the human eye, which is the color we observe.

If the gloss and smoothness of the paper surface are too high, the reflected light on the surface is a kind of specular reflection, which is not easy to enter the human eye. The color observed at this time is basically the color reflected through the ink layer. If the surface of the paper is rough and the gloss is low, the reflected light on the first layer surface will be diffusely reflected. At this time, the color we see is the mixed color produced by the main color light and the reflected light on the first layer surface. Because it contains white light components, it reduces the saturation of the main color light, so people feel that the color becomes lighter when observing the printed product. When measuring the offset ink with a densitometer, the density value decreases and the brightness increases.