The six major influencing factors causing color deviation in printing
Time:2025-08-25
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1、The influence of ink layer thickness and viscosity on the ink color of printed products
An appropriate printing ink layer is an important measure to ensure the ink color quality of printed products and prevent them from getting dirty. If the ink layer is too thick, its viscosity is bound to increase, which can easily cause paper fuzz and affect the uniformity of the printed ink color. If the printing ink layer is too thin and the viscosity of the ink is insufficient, the printed ink color will be too light and the visual effect of the printed product will be poor. As the running time of the printing machine increases or the printing speed speeds up, the coefficient of friction increases, and the temperature of the ink will gradually rise. As a result, the ink will become thinner and its viscosity will correspondingly decrease.
Therefore, when adjusting the ink, all these situations must be comprehensively considered to ensure that the batch of products obtain a relatively balanced printing ink color. However, in the actual production process, the decrease in ink viscosity is inevitable. Usually, the ink color of the printed matter is relatively dark at the beginning of printing, and then it will become lighter. This can be achieved by appropriately adjusting the rotation Angle of the ink transfer iron roller to increase the ink supply and keep the ink color intensity consistent before and after.
In addition, to prevent the viscosity of the ink from varying too much and affecting the balance of the ink color on the printed matter, the contact between each rubber roller and the ink-transmitting iron roller should not be too tight, and the rubber should not be too hard, so as to minimize the frictional heat and maintain an appropriate concentration of the ink.
2、The influence of printing pressure on the ink color of printed products
Printing pressure is one of the important conditions for achieving print transfer. Since the surface of the printing plate is not absolutely flat and the surface of the paper inevitably has slight unevenness and uneven thickness, if the printing pressure is insufficient or uneven, the ink color on the plate will inevitably be uneven in intensity.
Therefore, the ideal printing process is based on the "three flatness" (that is, the printing plate, the ink roller and the backing body are all relatively flat to achieve good contact conditions), and through the effect of balanced printing pressure, a relatively thin ink layer is applied to make the printed matter obtain a relatively uniform ink color. When the printing pressure is insufficient or uneven, there may be poor contact between the backing and the printing plate. Increasing the ink supply can meet the visual effect of the ink color on the plate. However, this not only increases the consumption of ink but also easily causes the printed matter to become dirty, which is not advisable.
3、The influence of rubber roller quality on printed products and ink color
In terms of letterpress and offset printing processes, whether the printed matter can achieve the desired ink color is closely related to the quality of the rubber roller. The equipment for printing color printed matter consists of three types: ink transfer rollers, ink distribution rollers and ink transfer rollers, totaling five or six, or even more than ten. Among them, the ink transfer rollers and ink transfer rollers have a greater impact on the intensity of the ink color.
The quality of rubber rollers is mainly reflected in elasticity, viscosity, roundness and surface finish, etc. Among them, the viscosity mainly affects the intensity of ink color. During the printing process, only by maintaining a certain degree of viscosity can the rubber roller ensure that the amount of ink applied to the plate surface is uniform and consistent in each printing cycle.
However, in the actual production process, the viscosity of the rubber roller is not stable. One reason is that the increase of paper dust in the ink affects the viscosity of the rubber. Secondly, the tackifier on the surface of the colloid (i.e., glycerin) is lost as the temperature rises and the usage time extends. The viscosity on the surface of the rubber roller gradually decreases, and the ink absorption performance correspondingly declines, thereby affecting the balance of the ink color of the printed matter. Therefore, for printing plate products, polyurethane rubber rollers with relatively stable quality should be adopted. If printing bulk products, the rubber rollers should be cleaned in a timely manner.
4、The influence of differences in the cleanliness of paper on the ink color of printed products
In fact, the relationship between paper and ink is complex. If we only consider the ink intensity of a book, it should be noted that the smoothness of the paper surface has a certain relationship with the ink color. If the pressure of each sheet is the same, the smoothness of the paper surface is inversely proportional to the ink consumption. Those who prefer smoothness absorb less ink, while those who prefer smoothness absorb more ink.
Therefore, when there is a difference in the smoothness between the front and back of the paper, the method of increasing the ink volume and pressure should be adopted as appropriate to make proper adjustments. In printing, it is customary to print the smooth surface first and then the rough surface. When printing, the pressure and ink supply should be appropriately increased to ensure that the ink color on both sides presents an ideal visual effect. Practical experience shows that the effect of adopting the above-mentioned method is much better than simply increasing the ink supply, and the printing quality is relatively good.
5、The influence of light changes on the ink color of printed products
Generally, there are three types of light sources for identifying the ink color of printed materials: sunlight, fluorescent lamps and electric lights. The luminescence conditions of these three light sources are different, and thus the colors of the light they emit are also different. The gaze is pure white light. Fluorescent lamps are white with a hint of blue, while electric lights are reddish with a slight yellowish tint.
Although daylight and fluorescent lamp light sources are somewhat similar, when identifying high-quality products, the differences between the two should also be taken into account. The influence of light on the identification of ink color is not only related to the light source, but also to the intensity of the light and the Angle of illumination. Under the same light source, the intensity of the reflected light on the sample image is mainly determined by the distance between the sample image and the light source; the closer it is, the stronger it is, and the farther it is, the weaker it is.
The correct Angle of illumination should be that the Angle of incidence is equal to the Angle of reflection. When light shines on the sample image, there is inevitably some refraction, but it has little effect on the identification of ink color. When identifying the ink color of printed materials, it should be done under the condition that the intensity of the light source and the Angle of illumination are the same, whether during the day or at night, to prevent color deviation or ink color variation caused by ink mixing errors.
6、The impact of inaccurate overprinting on ink color
For products with dot gradation, whether the overprinting of each color plate is accurate will have a significant impact on the printing hue. Accurate overprinting of the hue will result in a good effect, while inaccurate overprinting will cause some deviation in the hue of the printed matter. This is due to the difference in the positions where various color dots are superimposed, which inevitably leads to visual color differences.
Therefore, when printing web-patterned color products, the overprinting must be precise to ensure that the printed hue meets the process requirements. To prevent inaccurate registration and color deviation caused by the expansion and contraction variation of paper, for high-quality dot color products, it is advisable to use a multi-color machine to complete the superimposition printing in one go, so as to improve the registration quality. In addition, the paper should be hung and dried to reduce the occurrence of sheet variation during the printing process.
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Anna Zhang