My opinion on the allocation of spot color ink in

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My opinion on spot color ink allocation in packaging and decoration

in the printing process of packaging and decoration products, some four-color original products are not easy to achieve the ideal replication effect due to overprint problems and ink balance, while there is no overprint problem in spot color ink printing, and the ink balance is relatively easy to master

although spot color ink is convenient and fast to use, not all packaging products are suitable for spot color ink printing

for different prints, how to reasonably use spot color ink requires technicians to check, carefully analyze color samples or samples, and adopt accurate deployment methods to deploy spot color ink. Only in this way can we achieve the effect of half the effort

1. How to analyze the color manuscript or sample manuscript when mixing ink

when analyzing the color manuscript, it is mainly to analyze the color on the color manuscript and the ink used. The principle is: the three primary colors are the tones (4) project content: the basic colors of all ink colors, no matter how complex the colors change, can not exceed the range of the three primary colors

when analyzing the color manuscript, it is necessary to make clear whether the color manuscript is mainly printed by line or on-site. If line printing is the main method, we should focus on the consistency of the background color when allocating ink; If it is mainly based on field printing, the deployment place can focus on the same complexion; If there is both, then the color and complexion should be taken into account when mixing ink

after analyzing the color manuscript, analyze the color of the ink used, that is, for any kind of ink, be good at seeing the color components. For example: for yellow ink, we should be good at identifying whether it has red phase or blue phase (or green phase); For magenta ink, we should be good at identifying whether it is yellow or blue (or purple); For green ink, we should be good at identifying whether it is red or green (or yellow)

suppose green ink is mixed with green ink and yellow ink. If green ink has red phase, or yellow ink has red phase, the green obtained by mixing that line will not be dimmed, because this is actually equivalent to adding magenta ink to green ink and yellow ink, and even if this part of magenta is small, it should be mixed with a certain amount of cyan and yellow according to the principle of pigment subtraction method to form black (Yellow + cyan + magenta = black), and a small amount of black should be added to green, Its color science investigation shows that it is naturally dimmed, and the lightness and saturation are also greatly reduced

2. how to determine the hue and blending proportion of ink according to the chromatography

the blending of spot color ink usually requires a standard chromatography, a weighing balance and an ideal blending environment. First, according to the hue of the color sample, find the corresponding color block in the chromatography, and determine the proportion of yellow, magenta, cyan and black in the original color with the area percentage of the four color points marked by the color block

suppose 1000 grams of light green ink needs to be prepared, and the chromatography indicates 70% yellow (y) and 20% green (c), indicating that the light green ink is mainly yellow. Assuming that the printing area is 1, the proportion of dilution required should be 1-70%. According to the ink formula, the dosage of each component can be obtained

the mixing amount of ink used in a batch of live parts is related to the following factors:

1) paper specification

2) area of image

3) the number of prints

4) type of paper

5) specific gravity of ink used

6) loss

3. how to accurately allocate spot color ink

spot color ink allocation includes light color ink allocation and dark color ink allocation. All inks prepared by adding diluents to the original ink are light colored inks, which are mainly diluents and supplemented by primary color inks. Note:

1) select the appropriate diluent according to the color sample

2) determine the proportion relationship between the original ink and diluent according to the chromatography and the original sample

3) add the selected primary color inks successively from light color to dark color

4) add ink in the order of large to small according to the mixing proportion

5) after mixing evenly, scrape a small color sample with a scraper to compare it with the original sample, or open the ink on the paper (that is, dip the ink with the same volume as mung bean on the paper, and then cover it with another paper to compare the ink)

6) try to use less inks of different colors, otherwise the gloss of the prepared ink will be reduced and the ink will be gray

7) all the papers of the sample should be the same as the printing paper, and the observation of the color manuscript and the sample must be carried out under the same standard light source

the blending method of dark ink is basically the same as that of light ink, but it should be noted:

1) take the main color as the main ink, supplemented by other inks. When mixing, first analyze the light and dark relationship between the main color ink and the auxiliary color ink, then weigh the ink, place the main color ink on the ink mixing table, slowly add the auxiliary color ink and stir it evenly, and then observe the difference with the primary color sample by comparison until it is consistent

2) select the ink with the color close to the requirements for printing ink. According to the principle of subtraction, the mixed color will become gray. The more kinds of primary ink, the darker the color, and the lower the brightness and brightness of the color. Therefore, in the deployment of ink, we must choose the color ink that is similar to the color requirements to avoid the deployment of multiple color inks. For example, dark brown is usually mixed with red ink, yellow ink and a little black ink

3) pay attention to the color deviation of the ink. Ink usually has some color deviation, such as red mechanical equipment is essentially the same, blue, yellow, etc. when mixing ink, we must control the color deviation of each color of ink

4. Problems that should be paid attention to in mixing various colors of ink

when mixing spot color ink, in addition to complying with the operating procedures, the following must also be paid attention to:

1) ink mixing tools such as ink knife, ink mixing table (box), balance, etc. should be washed with gasoline and kept clean

2) main technical indicators of the universal mechanical experimental machine for College Teaching: keep the surrounding environment clean, wipe off the ink with a cloth, maintain a good working environment, and develop good operating habits

3) take good care of the residual ink returned from the machine, and do not dry and skin it for future use. It is best to pour some ink mixing oil into the remaining ink, and then cover it with oil paper

4) when viewing the hue with paper twist, the paper to be printed should be viewed under standard light source or natural light

5) when mixing ink, do not use the ink knife with colored ink to dig for ink or auxiliary materials of another color

6) when using barreled or boxed ink, do not use an ink knife to dig casually, but dig it layer by layer on the surface

7) do not blindly add other auxiliary materials to the ink

8) for inks with large amount, it is best to add the desiccant as soon as you use it, and add as much as you use it, so as to ensure the quality

9) record the proportion of allocated ink in time to facilitate the allocation of ink during the next printing

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