How to do the proofing and color of the packaging material printing process

Among the cosmetic packaging materials, there are many printing packaging materials. Among the printing packaging materials, the most important job is the color matching work of the proofing. The color matching and the color difference will not be related to the key quality problems. Supplier disputes can also improve the business efficiency of both buyers and suppliers! This article shares some basic knowledge about printing proofing and color, for the reference of friends who purchase packaging materials:

1. The importance of proofing and coloring of printed documents

Proofing is the best way to track the color difference. Without proofing, there is no basis for color matching. It is unreliable to rely on the design file alone, because the color difference of the computer is still very different from the actual printing. There is a conflict between the issue of color matching and purchasing, so as a qualified purchaser, you should pay attention to the issue of color matching and should understand. Proofing and coloring can also solve the contradiction of color difference very well, and color matching cannot rely on subjective Consciousness, the printing process is cumbersome, and each process has different chromatic aberrations. In addition, the process will also affect the chromatic aberration. For example, too dumb glue will make the overall color darker, which shows the importance of color!
2. Precautions for printing and color

1. For the film, pay attention to the fact that there should be no holes (light leakage) in the solid part. The edges and corners of each CMYK film must be completely matched, with no pattern or scratches.
2. The proofing draft must be carefully proofread, and the responsibility is great!
3. When signing, pay attention to the required paper, printing quality, delivery time, and post-process requirements. Don’t be sloppy!
4. Documentary.
Pay attention to the chromaticity of the printing (whether it is real or not, whether it is enough, whether it is heavy or light, it is mainly to compare the proofing draft, I often say this when I am documenting, the red is heavy, the youth is young, and the ink is a little thick…  …);
Alignment (that is, whether the edges and corners of CMYK are aligned, it is best to use a magnifying glass to see the error of lines 1 and 2);
Pay attention to whether there are obvious dirty spots in the light-colored part of the printed matter, point it out at any time, and let the printer clean the plate;
Pay attention to whether there are extra white spots or other color spots in the dark part of the printed matter, and erase them at any time;
For each part of the printing, the workers will take out a few sheets to look at the samples, and you will follow along. The printing press may run a certain color for a period of time. The phenomenon of running light or running heavy.

3. The problem of color matching of digital proofing

In printing production, it is difficult to follow the primary color (CMYK), mainly because the ink hue is different from that of the printer’s ink, and the primary color of the digital sample is synthesized by different proportions of CMYK ink. When printing CMYK monochrome, adding or subtracting ink will only change the depth of the color, not the hue of the color. Therefore, once the hue is wrong, the digital sample cannot be followed.

1. One color and color problem
In printing production, it is difficult to follow the primary color (CMYK), mainly because the ink hue is different from that of the printer’s ink, and the primary color of the digital sample is synthesized by different proportions of CMYK ink. When printing CMYK monochrome, adding or subtracting ink will only change the depth of the color, not the hue of the color. Therefore, once the hue is wrong, the digital sample cannot be followed.
2. Neutral gray and color problems
Neutral gray is also a color system that is difficult to follow. During the printing process, the dots of one of the color versions change slightly (even 1% of the dots change), which can be felt by the human eye. For printing, control the dots in Small changes are difficult.
3. The problem of dark tone and color of secondary color
Secondary colors mainly refer to C+M, C+Y, Y+M, C+K, Y+K, M+K. The dark parts of these colors are also difficult to completely match in printing and color, especially the blue-purple synthesized by C+M and the red synthesized by Y+M. Neutral gray is the same as the color, and the human eye is very sensitive to these colors. A slight change in the amount of ink supplied during printing will produce a great visual change.
4. Combination of large-area color blocks and images of the same color system
Large-area color blocks use a lot of ink, and it is easy to see the difference in color. When large-area color blocks and images are arranged in the same ink path, it is difficult to control the amount of printing ink to take care of both at the same time.
5. Combinations of Opposite Tones
When there are images with opposite main colors at the same ink key position, the printing is not easy to follow the color. For example, a blue sky landscape is arranged above, and a portrait of a person is arranged below. In order to highlight the blue sky above, the amount of C ink needs to be increased, and in order to highlight the skin color of the person, the C ink needs to be reduced. In this way, once the digital proofing is slightly deviated, the color cannot be followed by adjusting the amount of printing ink.
6. Spot color proofing and color
Judging from the current actual production situation, it is basically impossible to realize the simulation proofing of spot colors. The hues of spot colors are mostly based on standard chromatograms, and digital proofing is only for reference. In the proofing process, the spot color is generally converted into the ink CMYK four colors, and then the printing ink is used to simulate. When the spot color is converted into the CMYK overprint color process, errors are prone to occur.

Four, film proofreading pay attention to eleven major points

1. Check whether the required information is complete before proofreading
Layout/text/color/size (drawing) information
Design / production (modified) version
Film inspection form
Carton / Trademark Identification Card
2. Is each film dirty?
3. Are there any scratches on the film?
3. Are there any missing corners?
4. The layout and text are correct
5. Overprint accuracy of corner lines and various color versions
6. Is the pattern complete?
7. Is there any problem with the size?
8. Is there any bleeding?
9. Are there any color separation errors in each spot color version?
10. Are there any of the following at the bite position and around the film?
Product name (and output batch), size, color code, output date, producer code, color calibration bar
11. Check whether the angle of the network cable is heavy or not.