The gloss of the ink layer
Figure 2 shows two samples with different ink film glosses, but the ink itself has a uniform color. It can clearly be seen that the sample with high gloss is significantly darker than the other one. Why is this
Gloss refers to the degree of specular reflection on the paper surface. The higher the gloss. The higher the degree of specular reflection, the lower the degree of diffuse reflection. vice versa. When specular reflection occurs. The human eye sees reflected light only at a certain angle. The diffuse reflection of light can be seen at any angle. The ink film has a high gloss. This means that the degree of specular reflection on the ink film surface is so high that the human eye can see much less white light reflected by the surface than the low gloss ink film in most cases (except for certain angles), which makes the color saturation. Higher, so high-gloss prints look brighter and fuller.
Ink surface smoothness
Smoothness is a technical indicator for evaluating the degree of surface roughness. The smoother the better, the smoother, more even and smooth the surface. In general, smoothness is good and gloss is high. Therefore, the effect of the surface smoothness of the ink layer on the print is similar to that of the gloss.
The gloss and smoothness of the ink layer. It has a lot to do with the ink binder. If the ink binder resin film high gloss. With good smoothness, the color saturation of the printed product is high and the color is bright. therefore. Before deploying spot color ink. To first observe the gloss and smoothness of the customer's color sample, select the appropriate ink-matching spot color for its gloss and smoothness. Try to make the gloss similar to the color sample. When the plastic film is printed in spot color, the key is not the ink. It is the surface condition of the substrate. This is the time to select the same film that was used in the official printing process to make a test color sample.
Postpress
Many post-printing processes also have a great influence on the color of the ink. In particular, after printing or laminating, the color of the printed product will become more vivid and full. Greatly improved the quality of printed products.
In the deployment of spot color ink. It is necessary to anticipate the influence of the post-printing process on the color of the ink. In general. Artificial color matching is based on experience to estimate the degree of color change. When compensating ink, compensate again. The computer color matching, you can adjust the formula by a certain algorithm
Other factors
In addition to the above factors. There are many other factors that can cause changes in the printed ink layer, which can affect the color of spot colors. For example, the addition of various solvents, additives, and additives during the ink adjustment process. The concentration of pigment particles in the ink is often reduced, and the hiding power decreases to affect the transparency of the ink layer. In addition printing process. Printing pressure, printing speed, ink viscosity, number of plate screens, cell depth, and blanket change can all cause ink layer thickness changes. In particular, gravure printing inks are more volatile. Frequently adding solvents during printing to adjust the viscosity of the ink. To ensure its printability, the impact on the color of prints can not be ignored.
Conclusion
There are so many factors that affect the color of spot color printing. Is it true that the color of spot colors is really as difficult to control as some people say? In fact, it is not enough, as long as it is done properly in the color matching and printing process. Can better control its color. These measures are mainly the deployment of spot colors and standardized management of the printing process, so that the company's production environment remains stable. Just do it. Spot color printing is no longer difficult.
Wen/Gao Yanmei