Application of the hottest spot color in packaging

2022-09-22
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Application of spot color in packaging and printing

in order to better stimulate consumers' vision and stimulate their purchase desire, many manufacturers now like to use large areas of color blocks for product packaging design, especially in domestic tobacco and alcohol packaging design, they like to use large areas of red and yellow blocks or gold and silver blocks. In order to make the commodity packaging meet the expectations of customers, packaging and printing manufacturers need to pay close attention to the practical application of spot color in the production process, so as to avoid the product not reaching the desired effect of customers, which will cause customers' complaints, complaints and even return compensation

in packaging printing, two color printing processes are generally used. One is normal four-color printing, that is, medium yellow, magenta (or magenta), sky blue and black ink overprint are used to copy color originals; The other is spot color printing, which only uses ink other than the normal four colors that can accommodate five passengers to copy the original. When printing a large area of ground color, spot color printing is more commonly used. If Jinan experimental machine factory sincerely thanked the new and old customers in 2016 that the manuscript contained many pictures of different colors, it would need to be scanned and separated by electronic color separation machine or color desktop system, and then produced by normal four-color printing process. If the product manuscript is composed of uniform color blocks of different colors or regular gradual color blocks and words, spot color printing can sometimes be selected under the condition of comprehensively considering improving printing quality and reducing overprint times

the ink prepared by spot color printing obtains the color according to the principle of pigment subtraction, and its color has low transparency and high saturation. Spot color blocks with uniform ink color are usually printed on the spot, and the amount of ink should be appropriately increased. When the thickness of the ink layer is large, the sensitivity of the change of the thickness of the ink layer to the color change will be reduced, so it is easier to get a uniform and thick printing effect. Due to the uneven technical level of current paper manufacturers, the color of the surface of the paper of the same specification will appear more or less deviation, or blue, or yellow, which brings trouble to the packaging and printing manufacturers to control the color of products. If the opacity of spot color patches can be reasonably and properly used, the above problems can be well solved

and the comprehensive effect of subtractive absorption and additive mixing of dots is obtained by using four-color printing, with high brightness and low saturation of color blocks. For light color blocks, the four-color printing process is adopted. Due to the low coverage of the ink on the paper, the ink color is flat and lacks a sense of thickness. Due to the point angle, people will inevitably feel the existence of patterns. In addition, the color block overprinted by the four-color printing process is composed of a certain proportion of dots. When printing dots, the thickness of the ink layer must be strictly controlled. It is easy to change the color intensity and dot expansion due to the change of the thickness of the ink layer and the change of the printing process conditions, resulting in color changes and uneven ink color. If you can't use a multi-color machine to print the color of the color block at one time, it is also easy to appear color deviation because the color of semi-finished products is not easy to control. For example, sky blue and magenta are overprinted into purple. If the amount of sky blue ink is large, it will be blue, and if the amount of magenta ink is large, it will be red. At this time, it is advisable to change the overprint color block into a special purple version. Although there is an additional printing plate, the printing preparation time is shortened, the printing speed is improved, the hue control is stable, the production efficiency is improved, the waste products are also reduced, and the overall production cost is also reduced. Of course, this phenomenon should be taken into account in process planning

when printing a large area of light color uniform color block, it is usually used to add diluent to the original ink to prepare the spot color ink, and then carry out field printing, so that the ink layer is thicker, and it is easier to get the effect of uniform and thick color. If the four-color printing process is adopted, a low percentage of flat spots must be used, but the low percentage of flat spots is easy to be smaller in some parts due to small sand particles or slightly poor air extraction, including food and beverage, during printing, resulting in uneven ink color. When printing, it is easy to cause poor ink transfer of small dots due to excessive water supply in the layout, accumulation of paper powder on the printing plate and blanket, and low smoothness of the paper, resulting in shallow ink and uneven ink, resulting in batch color difference and increased waste products

for dark large-area color blocks, the four-color printing process may need to be superimposed by high percentage points of several colors. The ink layer is too thick, and the back is rubbed dirty. With spot color printing technology, only one color needs to be printed, which is not easy to get dirty on the back. With the four-color printing process, some parts of the picture and text may be composed of several colors, while with the spot color printing process, only one color is printed on the corresponding parts to avoid overprint errors

the above introduction is the application of spot color ink prepared with three primary colors. In fact, in packaging and printing, in addition to the ink mixed with three primary colors, there is also an ink that people like very much - metal ink. Because of its special metallic luster, metal ink has been widely used in packaging and printing, especially in tobacco and alcohol packaging and printing. The commodity packaging with metal ink looks elegant and noble, which can well improve the grade of commodities. However, due to the poor adhesion of metal ink itself, it is more difficult than ordinary spot color ink in actual printing

there are two kinds of common metal inks, namely gold ink and silver ink. Gold ink is made of copper zinc alloy, so the powder is mixed with gold blending oil. The content of copper and zinc in gold powder is different, and the color of gold ink is also different. The content of zinc is low, and the color of gold ink is reddish; If the zinc content is high, the golden ink will be blue in color. At present, the gold powder (ink) sold in the market can be divided into red gold powder (ink), cyan red gold powder (ink) and cyan gold powder (ink). Silver ink is made of silver aluminum powder and silver blending oil. Silver powder with different particle sizes produces different metallic luster. Silver powder with coarse particles has strong metallic luster. Properly adding some auxiliary agents such as bright yellow, bright oil, red drying oil and dibutyl in the gold and silver ink can enhance the affinity, viscosity and fluidity of the gold and silver ink, improve the adhesion of the gold and silver ink, and thus improve the printing transmission performance of the gold and silver ink

when printing gold and silver ink, there are generally two ways. One is to base it first and then print gold and silver ink, that is, to use ink with strong hiding power and similar color to gold (silver) ink. Gold ink uses light yellow ink, transparent yellow ink or false gold ink to make the background color. In order to improve the metallic luster, about 10% gold ink can also be added. The silver printing ink is generally made of false silver ink. The fake silver ink can be prepared by diluting agent, white ink, black ink, debonding agent, No. 6 ink mixing oil and white dry oil in a certain proportion. The printing adaptability of silver ink is better than that of gold ink. It can basically meet the requirements of general packaging printing products with only one printing. If you encounter some packaging products with large area of silver printing or the paper used is poor, you need to take two times of printing to show the silver luster well. This method requires higher technical level of printing operators and is more difficult. The other is to hollow out the position where gold and silver ink is printed on other color plates, and the gold and silver ink is printed directly on the paper. This method can be well mastered by ordinary printing operators. Moreover, if the color of the product plus gold and silver is four colors, the four-color offset press can be used to print all the colors, including gold and silver ink, at one time, so as to save time and shorten the construction period. However, in the prepress process planning, attention should be paid not to allow gold and silver color blocks and other color blocks to be hard overprinted, and 0.1 ~ 0.2 mm trapping should be set. In addition, it should be noted that after printing the gold and silver ink, the printed matter should not be in a hurry to dry, because the drying speed of the gold and silver ink is slower than that of the general ink. Don't try to add more drying oil quickly, otherwise the gold and silver ink particles will become thicker and the ink on the ink roller will increase, which will cause the printed matter to adhere

in short, spot color printing is a flexible and complex color printing process, which should be used properly and reasonably. In the actual production process of printing and packaging, sometimes spot colors are used alone, but often two or three of the normal four colors plus one or two spot colors are used in combination. Whether to use spot color depends on whether it is conducive to reducing the scrap rate and improving the product quality; Is it conducive to saving time, shortening the construction period and improving production efficiency; Is it conducive to reducing production costs and increasing enterprise income. This requires the process technicians of the packaging and printing manufacturer to comprehensively consider the process technology level of the factory, the skills of operators and the use of machinery and equipment when planning the process, so as to prepare a reasonable production process

reprinted from: print magazine

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