Deployment skills and precautions of the hottest p

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The deployment skills and precautions of ink color in packaging printing

in the printing process, no matter how it is printed, whether it is multicolor or monochrome printing, the primary problem encountered before printing is the deployment of ink color, so it is often necessary to choose and deploy ink color. The allocation of ink color is the most important part in printing. The true reproduction of color directly affects the product quality and market share. In some large-scale enterprises, there are not only special allocators, but also the best way to satisfy customers. Next, I will explain how to improve the quality of ink through the blending skills of ink color:

color matching principle

any color is represented by three characteristics: hue, lightness and saturation, so the above three factors must be considered in the color matching process. Although in theory, black is the complete absorption of light, black ink still has luster. Ink is made by grinding pigment (toner) and resin binder. The particles of the pigment are surrounded by a layer of almost transparent resin oil. This layer of tree, especially the microcomputer controlled pressure testing machine, is not only high-precision, but also has the function of refraction and reflection of light. Therefore, we can feel that the black ink printing still has a certain gloss on the substrate. Pigment usually accounts for% of the ink composition. Its dosage determines the ink concentration and has a great impact on the ink, such as the relative density, transparency, heat resistance, light resistance and chemical resistance of the ink. In the process of ink color matching, the ink used should be determined according to the actual printing process, ink layer thickness, printing substrate and other conditions. When selecting ink, the gloss, hue, coloring power and hiding power of the ink itself should be considered

1) gloss: gloss can be measured by instruments or judged by the naked eye. Usually, in the process of color matching, it is only observed by the naked eye

gloss actually refers to the degree of the ability of ink printing samples to reflect light in the same direction after being irradiated by light. It directly affects the appearance of printing and is a very important indicator. At the same time, when choosing ink, we should distinguish whether the ink itself is bright, semi gloss or matte ink, and we should also consider whether it is the same ink, such as internal printing ink or surface printing ink. The same ink must be mixed to avoid mixing errors and unnecessary losses

2) hue is the basic feature of color, which is used for qualitative difference. When matching colors, we should first consider whether the hue is consistent. Its detection method is usually to scrape the color with scraping paper or simulate printing, and observe and compare the standard and sample with human eyes

3) hiding power is the degree to which ink covers its background color. The better the hiding power is, the worse the transparency is. The transparency affects the efficiency of ink chromaticity and the degree of influence by the printing substrate

4) tinting power is a method to indicate the concentration of ink. Its measurement is to dilute and mix a certain amount of ink with a certain number of times the amount of standard white ink, and then compare it with the standard sample. The strength of tinting power reflects that the degree of ink mixing affects the thickness of printing film. Through color identification (scraping test of scraping paper), the differences in gloss, hue and hiding power between the ink sample and the standard sample can be compared

the specific methods are as follows: put standard ink in the upper left corner of the identification paper and color matching ink in the upper right corner. Use a scraper to flatten the thin part at an angle nearly perpendicular to the color scraping paper and quickly expand the thick part with light force at an inclined angle. After the ink surface is dry, the ink hue can be observed in the thin part, and the ink coverage and transparency can be identified in the black belt part; Judge the gloss difference between the two in the thick part and observe the whole color appearance. Usually, white scraping paper is used for black and color inks, while black scraping paper is used for white inks

when observing the color samples, it is best to compare them under the indoor indirect light source in the daytime, and it is not suitable to be directly exposed to the sun. When observing samples at night, it is recommended to use fluorescent tubes for color evaluation and color temperature of 5000 ± 200~k, or use self-made mixed light sources: three 6500k400w fluorescent tubes, two 20W blue fluorescent tubes, and six 100W tungsten filament lamps. Fix them in a special cover, mainly for the convenience of observing color samples

color matching precautions

1) carefully observe the color sample, pay special attention to the printed substrate, and select the ink from the roughness and smooth reflection of the substrate. For example, the ink is printed on a smooth and highly reflective aluminum plate or can. Choosing an ink with high transparency will help greatly enhance the metallic luster of the ink

2) when selecting the ink required for color matching, try to avoid mixing too much ink, and try to use ink close to the standard color and made of a single pigment. Too much color ink is used for color matching. The farther away from the standard color, the worse the brightness is, and the higher the matte degree of the mixed color is. It is impossible to use color matching to modulate the primary color. Therefore, two kinds of mixing can be used in color matching, so there is no need of three kinds, the less the better

3) pay special attention to the coloring power of the ink. If the selected ink concentration is not high enough, no matter how it is combined, it cannot reach the standard color concentration

4) when white and black inks need to be added, special attention should be paid to the added weight and the accuracy of weighing. Among all inks, white inks have a strong hiding power. Adding too much will not only dilute the color, but also prevent the reflective degree of the substrate. However, for printing uneven substrates such as nylon cloth and paperboard, in order to ensure the appearance of the print, it is best to print a layer of white as the background color. Due to the strong coloring power of black ink, if you are careless and add too much, you need to add a considerable number of other color inks to adjust the color, resulting in waste, so you need to pay special attention

5) when making light colored ink, we should judge how much white ink should be added from the light transmittance of the ink film or adjust the ink to solve the above problems. It is absolutely not allowed to use solvent (dilution water) to dilute the color. Too much solvent will not only affect the printing performance, but also damage the ink structure, resulting in the separation of pigment and resin oil, precipitation, or greatly reduce the gloss and brightness of the ink

the allocation of dark and light inks

the allocation of ink can be divided into the allocation of dark ink and light ink. The so-called deployment of dark ink refers to the deployment of only primary ink without adding any diluent. During deployment, according to the amount of ink required for printing, and based on the main color ink and auxiliary color ink and their proportions determined by color analysis, the main color ink and auxiliary color ink are blended evenly. The deployment of dark ink is divided into three kinds: monochrome, interchrome and polychrome. Monochrome refers to the blending of a primary color ink. Intermediate color refers to the blending of two primary color inks. Multicolor refers to the blending of three primary color inks

ink prepared by adding diluent is called light color ink. Pay attention to three points when mixing:

1) use white ink without diluent

2) white ink is mainly used in color matching, and a little color ink is added to white ink; 3) The color selection should be accurate, as follows:

Pink: mainly white, slightly peach red, fluorescent orange

jade: mainly white, slightly medium yellow, fluorescent orange

Beige: mainly white, slightly dry, medium yellow, slightly black

light blue: mainly white, slightly medium blue

lake blue: mainly white, slightly pore blue

gray: mainly white, slightly pore blue, slightly yellow

silver gray: mainly white.Mainly, with a little silver paste Black ink

snow blue: mainly white, slightly red, magenta

flesh color: mainly diluent, slightly transparent orange red, medium yellow

ivory color: mainly diluent, slightly yellow, malachite blue, orange red

how to improve the gloss of ink film

1) add an appropriate amount of inking oil within the allowable range of color concentration

2) coat the surface of printing film with varnish or inking oil

3) increase the transparency of the ink, choose high transparency ink or add an appropriate amount of ink blending oil, use smooth, strong reflection, and the reflection of the substrate to increase the gloss:

4) prevent the adsorption of the substrate surface, and reasonably improve the smoothness of the substrate printing surface

5) pay attention to the temperature and humidity of the printing environment. In the case of high humidity and low temperature, when plastic intaglio printing is carried out, due to the fast evaporation speed of the solvent, it absorbs the heat around the ink film, causing the water vapor in the air to condense sharply, forming a fog on the surface of the printing ink film, resulting in the loss of gloss of the ink layer. In the rainy season, in the production of injection molding packaging materials, special attention should be paid to controlling the temperature and humidity of the printing environment to ensure good printing effect. Generally, the room temperature is best at% and the humidity is better at 40%, which is conducive to the true reproduction of color

production of special colors

1) gold and silver ink production: use ink mixing oil to add an appropriate amount of gold and silver powder and stir evenly. Pay attention to the selection of gold powder and silver powder with appropriate fineness. At the same time, choose the inking oil that conforms to the printing substrate, and prepare it during printing to prevent the ink from precipitation and stratification due to too long rotation time. Gold ink can also be mixed with silver powder, transparent yellow and inking oil

2) pearlescent ink: how to break the dilemma faced by the new chemical materials industry in the "1035" period? Huang Yinguo, consulting CEO of China Chemical Information Center, told China chemical news that the high transparency ink or inking oil is mixed evenly. The covering power of the ink is strong, and the pearlescent effect can be lost

3) luminous ink: the ink has the effect of absorbing light energy and then emitting light within a certain period of time, so it often shines at night. It is called luminous ink or phosphorescent ink. Usually, noctilucent pigments are dispersed in ink blending oil with high transparency and stirred evenly

the above inks cannot be ground. Gold ink and silver ink grinding will damage the grinding equipment. Pearlescent, luminous and ink grinding will damage the surface or crystal structure and lose its due effect

color matching of plastic printing

1) the color matching of printing ink should use the stereotyped ink with the same hue produced by the ink factory as far as possible, and the color degree of the stereotyped ink should be higher than that of two color inks

2) if you want to use 12 kinds of inks for color matching, you should try to use the stereotyped inks with similar colors for blending

3) in color matching, try to reduce the variety of ink, because the more varieties of ink in color matching, the higher the achromatic proportion, which will reduce the brightness and chromaticity of the ink, so if you can mix two colors, you don't need three

4) plastic film is a non absorbable material, so thinner should not be used to dilute the color ink, but white ink should be added to dilute it

5) different manufacturers and different varieties of inks are not mixed. This will affect the gloss, purity and drying speed of white ink

to sum up, when mixing ink colors, we must carefully grasp every pass before we can mix good colors

reprinted from: China Hong Kong silk screen printing

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