In the colored light addition method, the three colored lights are added in equal proportions and mixed to form white light. Blue and green light are mixed into blue light, blue and red light are mixed into red light, green and red light are mixed into yellow light and so on. These phenomena are unacceptable to most people, because people's extensive practice is subtractive color method-the addition of colored bodies, such as drawing color pictures, paint color matching, etc., are the principles of subtractive color method, and for a For a famous offset printing operator, not only should he understand the principle of color light addition, but more importantly, how to use the principle of subtractive color to guide the actual operation. In the actual printing, spot colors are sometimes used as a setting according to the original design needs. In addition, some products printed with four-color primary inks are not easy to control due to overprinting problems and water-ink balance, and it is not easy to achieve the ideal copy effect. Sometimes, spot color printing is also required, especially in packaging and decoration printing. , More choice of spot color printing. One should carefully analyze the color draft or sample draft before mixing the ink. When analyzing color drafts, it is mainly to analyze the colors on the color drafts and the inks used. The basic principle is that the three primary colors of the colorant are the basic colors of all the ink colors, and they never change. At the same time, it is necessary to understand as much as possible whether the color draft is based on screen printing or on-site printing. If screen printing is the main method, the ink should be focused on the consistency of the background color. If printing on the ground, the ink can be focused on the face color. If both are used, the background color of the ink should be adjusted. Both look and look. When the color draft is analyzed, the color of the ink used should be analyzed. Generally speaking, the operator or captain of the ink preparation is particularly sensitive to the observation of the color of the ink. It can be seen that the components, such as yellow ink, must be good at identifying it Whether it is yellowish or blueish (or greenish), for magenta ink, it is good to identify whether it is reddish or blueish (or purple), and for cyan ink, it is good to identify it is reddish The phase is still green (or yellow). If green ink is mixed with cyan ink with red phase and yellow ink with red phase, the green color obtained by mixing will become dark, because this is actually equivalent to adding magenta ink (yellow + cyan + magenta) to cyan ink and yellow ink Red = black), therefore, the observation of the ink color is an essential basic skill for offset operators. Second, the basic principle of mixing spot color ink Whether it is dark or light color spot color inks, the basic principles should be followed when blending. This basic principle is based on printing colorology and printing technology. The main contents include the following ten points: (1) Try to use the same type of ink and the same type of auxiliary materials. In addition, the colors that can be formulated with two primary color inks do not need to use three primary color inks. In the same way, if a certain intermediate tone is needed, the intermediate ink must be used to avoid reducing the brightness of the ink and affecting the color and vividness. When mixing dark ink, the main color ink should be placed in the ink adjustment tray according to the weight of the ink used, and then the auxiliary color and necessary auxiliary materials should be added gradually. (2) The primary ink or primary color or dark ink is supplemented by the diluent, and the formulated inks are collectively referred to as light inks. The preparation method of light-colored ink is slightly different from that of dark-colored ink. The dark ink is gradually added to the light-colored ink. Do not take dark ink before adding light ink, because light ink has poor coloring power. If you add light ink to dark ink to adjust the hue, it will often make the ink more adjusted. (3) A small sample should be prepared before mixing the spot color ink. This means that the ink color to be used is preliminarily judged according to the hue of the original, and then a small amount of ink is weighed from each color ink according to the proportion, accurately weighed, placed on the ink adjustment table and evenly mixed, and the small color sample and Check it as is, make relevant records, and keep it properly. (4) When deploying multi-color spot color inks, use complementary color theory to correct color shift. For example: when the purple smell is heavy in a certain color ink, yellow ink can be used to correct it; if the red smell is heavy, blue ink (such as peacock blue or sky blue ink) can be added to correct it; when the black ink is yellowish and black , Can add a small amount of light blue as a color material, because light blue is blue ink with red light, which is conducive to improving the blackness of black ink. (5) Master the hue characteristics of commonly used inks. In the actual operation process, we must master the hue characteristics of commonly used inks. For example, when blending light lake green ink, sky blue or peacock blue should be used. Never use dark blue for blending, because dark blue ink has a red smell. After adding it, it will inevitably make the color darker and not brighter. Yellow ink, and the lighter yellow ink with a lighter blue effect is better, for example, when red orange ink is used, try to use gold red ink, because the color of the gold red ink is yellowish red, which can increase the vividness of the ink. In addition, the selection of some inks should be based on the effect of the screen. For example, the selection of inks for printing portraits and landscapes should be different. (6) Pay attention to the proportion of different inks. The specific gravity of inks is generally different. Ink with similar specific gravity is easy to mix, and inks with large differences in specific gravity will cause printing problems. For example, green ink formulated with lead chromium yellow ink and peacock blue ink with specific gravity, After a long time, the color ink with a small specific gravity will rise, and the one with a large specific gravity will sink, so a "floating color" disease occurs. If yellow ink made of organic pigments is used instead, the disease will be gone. In addition, due to the large proportion of white ink, in addition to a small amount of coverage requirements and color matching, try not to use white ink to dilute (if the live parts of the film are separately discussed), to prevent poor color stacking, color fade and other quality problems. (7) Reasonably choose diluent to master the degree of diluting. When the hue and the amount of ink used are determined, the diluent must be selected reasonably. For example, the diluent used in printing offset paper and coated paper is different. In addition, the degree of dilute is an important technical link. If the dilute ratio is small, the surface of the printed product is prone to bloom, the ink layer is shriveled, and the color is not bright; if the ink is too dilute, only the thickness of the ink layer can be increased to achieve the printing needs. Hue, so it is easy to make the low-key areas of the layout appear pasted, so that the depth is not clear. At the same time, there will be through-printing phenomenon. In addition, for the original ink that is not resistant to light and resistant to oxidation and easy to change color, try to avoid using light-colored ink to avoid color instability. (8) The preparation of spot color ink scraping paper should be consistent with the printing paper to avoid color differences caused by different papers. (9) Pay attention to the same density as the printed sample when preparing the spot color ink. In general, when the newly adjusted ink is close to the color of the printing sample provided by the customer, the color change will occur after the new ink is dried, so the newly adjusted ink cannot be lighter than the printed sample. (10) Take into account the characteristics of post-press processing. When selecting inks, the post-press processing should be considered. If the printed product needs to be glazed, general ink can be selected. If the ink with good friction resistance is selected, not only the cost is high, but also the glazing effect is affected. [next] Three methods of mixing spot ink Ink preparation refers to the process of mixing one or more inks together and adding certain auxiliary rib materials to adapt it to printing needs. The ink preparation mainly includes two aspects: on the one hand, it refers to the color adjustment of the ink, and on the other hand, it refers to the adjustment of the ink printing suitability. An important criterion for measuring the quality of printing is: the color must meet the requirements of the original. For the innumerable colors reflected in any color manuscript, the ink should be identified and recognized when the ink is prepared. This needs to be studied from the nature of color. As mentioned above, color has three characteristics, namely hue, brightness, and saturation, which are called the three attributes of color. The identification of any ink color can be distinguished according to the three attributes of color. Therefore, the theory of the three attributes of ink color is an important basis for the correct understanding and differentiation of various ink colors. . (1) Basic knowledge of ink preparation Ink preparation is a very detailed technical work, which should be carried out in a special room, mainly to grasp the hue and prevent sand and dust from falling into the ink. Equipment and reference material for ink preparation (1) Ink-adjusting worktable: a hard and smooth surface table (or slate) can be used as a worktable. In addition to the recipe, the ink samples and the printed samples should be saved. The surroundings of the room should be kept clean and tidy, and the walls must not have other bright colors with large areas. Because the environmental color has a great influence on the correct color discrimination. This phenomenon is called color illusion, and it is also a gray color block, which is reddish in a green environment and blued in a red environment. The same piece of color, surrounded by dark colors, it appears light. There are light colors around it, it looks darker. Therefore, when arranging inks, whether you are looking at the color samples of the original or the ink samples after ink adjustment, you must avoid the influence of the environmental color. (2) Method of mixing spot color ink For the duplication of continuous adjustment originals, it must be obtained by combining dots. For field manuscripts, if the four-color dot combination method is used, the copying is extremely difficult, the copying effect is not good, the colors are blurry and unreal, and the hue is also easy to produce deviations. . 1. The deployment of dark ink Use only three primary colors or intermediate color primary inks without any diluent for ink preparation, collectively called dark ink preparation. The deployment of dark ink is equipped with the following steps: (1) According to the color forming rule of the subtractive color method of the color material, compare the original color sample with the chromatogram, analyze and determine the proportional relationship of the content of the three primary colors in the color sample, and discharge the order of the main color and the auxiliary color. (2) Use the same type of three primary inks as spares. For fine products, use bright light quick-drying inks; for general products, use resin inks. (3) After determining the amount of blending, then add the ink in order from the largest to the smallest in accordance with the proportion of blending. Weigh the main primary color with the most content first, then weigh the auxiliary color with less content, and then add the auxiliary color ink to the main color ink in several times, and mix it evenly. (4) Use the three primary colors to mix and match a series of shades of shades such as brown, fake gold, red purple, bronze, olive green, etc. During the preparation process, you must pay attention to the accurate hue. In addition, you must master the dry oil. Add volume and use different dry oil according to different hue. Table 2-2 Three primary colors ink color change rule table Table 2-3 Inter-color ink blending table Table 2-4 Compound color ink formulation table Table 2-5 Hue and color deviation of commonly used inks 2. The deployment of light-colored ink Anything based on diluent or white ink, supplemented by dark ink, is generally referred to as light-colored ink preparation. When blending, the dark ink of the desired hue is gradually added to the appropriate amount of diluent and blended evenly until it meets the color sample requirements. The types of diluting agents are: white oil, weili oil, desalting agent, brightening pulp, white ink, etc. When mixing light-colored inks, three different methods are commonly used: The first one: the dilute blending method mainly based on Weili oil, white oil, desalting agent and so on. The light color ink prepared by this method has a certain degree of transparency and no hiding power, but the color of the ink is not clear. It is very suitable for overlapping overprinting of ink and plays a role in making up for the lack of main color. It is generally used for light red, light blue, Light gray ink, etc., to supplement the magenta, blue, black version of the tone atmosphere and layer. The second method: the whitening-based color matching method. The light color ink prepared by this method has pinkish color and fresh ink color, but has strong hiding power. Due to the heavy texture of the pigment, it is easy to stack plates, stack blankets during printing, and has poor light resistance. It is suitable for printing on the ground. It is better not to use alkaline zinc oxide white ink. The third type: the blending method of adding white ink with white oil and velvet oil. In this method, the white ink plays the role of color enhancement, and the prepared light-colored ink has different hiding power and transparency according to the different amounts of white ink. The hue of inks prepared by different methods depends on the hue of the ink blended on the one hand, and the diluting method on the other hand. E.g: Although the above four kinds of light red and light blue, pink and lake orchid are mixed with the same amount of dark ink, their hue is different. Light red, light blue dull, dull color; pink, lake blue are bright, beautiful and bright. [next] Sometimes, in actual production, the customer only provides the color name, and the color name is still a foreign name. The color spectrum has only the proportion of the color, and there is no color name, which often brings some difficulties to the ink adjustment work. This requires the ink adjustment worker to Summarize in practice, for example: Christmas red → yellow 100%, red 100% When mixing light-colored ink according to the corresponding proportion of each color dot of the color spectrum, you can refer to the following formula to calculate the approximate proportion of dilution required. Example 1: Light green on the chromatogram (yellow 50%, blue 30%) Assuming the required diluent is X, then light green = yellow 50% + blue 30% + X Example 2: Light brown on the chromatogram (yellow 30%, magenta 20%, cyan 20%) Assuming that the required diluent is X, then light brown = yellow 30% + magenta 20% + cyan 20% + X [Expert Tips] In the preparation of light-colored inks, white ink should be used as little as possible, but it is not to say that white ink is not used. Although the white ink cannot be completely used as a diluent. But white ink does have a dilute effect on deep ink. In recent years, due to the trendy design, the colors have become more abundant, and the light colors formulated with white ink are indeed beautiful and bright, with bright colors. In addition, white ink is easy to accumulate ink during printing, and its transferability is poor, but it cannot be used to exclude the use of white ink. The most important thing is to respect the opinions of customers. 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(2) Ink adjustment knife: Two ink adjustment knives (preferably one wide and one narrow) can be adjusted evenly.
(3) Bench scale, scraper, scraping paper, and ink tray box.
(4) Recipe record should record the proportion of each component and multiple additives each time (5) Color table (spectrum)
The light red is mainly composed of Weili oil, desalting agent, etc., and slightly pink or orange.
Pink is dominated by white ink, slightly pink or orange.
The light blue is mainly made of Weili oil, with a little peacock orchid.
Lake blue is dominated by white ink and slightly peacock orchid.
Table 2-6 Reference Table for Light Color Ink Blending
Coral red → yellow 50%, red 70%
Bellflower Color → Magenta 70%, Cyan 70%
Turkish blue → yellow 20%, green 80%
If the color → yellow 80%, green 10%
Naples Yellow → Yellow 70%, Magenta 10%
Almond yellow → yellow 50%, magenta 30%
Amber → yellow 80%, magenta 50%
Royal Purple → Yellow 30%, Magenta 100%, Cyan 80%
Navy blue → Magenta 90%, Cyan 100%, 50%
Olive → Yellow 90%, Magenta 30%, Black 80%
Mustard color → yellow 100%, magenta 10%, black 30%
Prussian Blue → Yellow 40%, Magenta 70%, Cyan 100%
Wool color → yellow 30%, magenta 20%, cyan 20%
Bottle Green → Yellow 60%, Magenta 50%, Cyan 90%
X = (100-50) + (100-30) = 50 + 70 = 120
The actual ratio is: yellow ink: green ink: diluent = 5: 3: 12
That is, 12 parts of diluent is needed when preparing the light green ink.
X = (100-30) + (100-20) + (100-20) = 70 + 80 + 80 = 230
The actual ratio is: yellow ink: magenta ink: cyan ink: diluent = 3: 2: 2: 23
When the light brown ink is used, 23 parts of diluent are needed.