Influence of Ink Layer Thickness on Color Rendering Effect (1)

[Abstract] When the thickness of the same color mixture or the brightness of the illumination source changes, the hue, brightness, and saturation will all change. In this paper, through the experimental study of the changes in the concentration (thickness) of the colorant, the phenomenon of coloration when the same ink is different in thickness is analyzed to discuss the effect of ink layer thickness on the color rendering effect.

[Key words] color mixing, inter-color, chromaticity diagram

For the same ink, the color properties may change when the thickness of the ink layer changes, which will have a certain influence on the reproduction of the printing color, especially the screen printing spot color control. The change of the ink layer thickness has different effects on the color rendering effect of the primary color, the inter-color, and the complex color ink. The two inter-color materials tend to be darker after being mixed, exhibiting a dark color or even a black color with a certain color tendency. How to explain the phenomenon of color mixture coloration, what are the rules of color mixture coloration, are worthy of in-depth discussion.

1. The color appearance when the same ink layer thickness changes

The same weight of the inter-color pigment red ink and green ink were mixed, respectively, using the Dutch IGT C1 type printability instrument to mix the ink to make small samples (ink unchanged, only change the amount of ink) to get the same ink printing The color samples of different ink thicknesses are shown in Figure 1. The thickness of the ink layer is determined by analyzing the weight of the prepress and post print plates weighed by the balance. Table 1 shows the test data of the ink layer thickness changes when different inks are mixed. Their hue and saturation are reflected in the CIE xy chromaticity diagram, as shown in FIGS. 2a-d, and FIGS. 2b-d are the image of FIG. 2a. Partial enlargement.

Table 1 Test data of ink coloration when ink layer thickness changes

Note: First mix the ink, use the Dutch IGT C1 type printability instrument to mix the ink to make a small sample (the ink is unchanged, only the amount of ink is changed, the unit of ink is ml), and the same ink is used to print different Ink thickness color sample. Use the SC-1 Smart Colorimeter to measure data. The ink used was Tiens brand.

(to be continued)