The Difference Between Spot Color And Four-color Overprint Color Block Visual Effect

The difference between spot color and four-color overprint color block visual effect

1. What is the difference in the visual effect of the color between the spot color printing color block and the four-color superimposed color block?

The ink prepared by spot color printing is obtained according to the principle of subtractive color mixing of color materials, and its color brightness is low and saturation is high. The spot color block with uniform ink color is usually printed on the spot, and the amount of ink should be appropriately increased. When the thickness of the ink layer on the layout is large, the change of the thickness of the ink layer will be less sensitive to the color change, so it is easier to obtain a uniform and thick ink color. printing effect.

The color block printed by the four-color printing process is mostly composed of a certain proportion of dots. When printing the dots, the thickness of the ink layer must be strictly controlled. It is easy to change the thickness of the ink layer and print Changes in process conditions cause changes in color intensity and dot increase, resulting in color changes; and because the change of any color that composes the color block will cause the color of the color block to change, resulting in the chance of uneven ink color It will be multiplied, so it is not easy to obtain the effect of uniform ink color for the color blocks printed by the four-color printing process. If a multi-color machine cannot be used to superimpose the color of the color block at one time, it is easy to cause color shift because the color of the semi-finished product is not easy to control. In addition, four-color printing obtains the combined effect of subtractive color mixing and additive color mixing of dots, with high brightness and low saturation of color blocks. For light-colored blocks, the four-color printing process is used. Due to the low coverage of the ink on the paper, the ink will appear flat and lack a thick feeling. Due to the angle of the network cable, it will inevitably make people feel the existence of the pattern.

2. From the perspective of improving product quality, what kind of products are suitable for spot color printing?

When printing a large area of light-colored uniform color blocks, usually add a diluent to the original ink to prepare the spot color ink, and then perform solid printing, so that the ink layer is thicker, and it is easier to obtain a uniform and thick color effect. If you use a four-color printing process, you must use low-count flat screen dots. However, the flat screen dots with low percentages are prone to smaller dots in individual parts due to tiny sand grains or slightly poor air extraction during printing, resulting in uneven ink color. During printing, it is easy to cause poor ink transfer of small dots due to excessive water supply on the layout, accumulation of paper powder on the printing plate and blanket, and low paper smoothness, resulting in light ink color and uneven ink color. For dark and large-area color blocks, the four-color printing process may need to be superimposed by several colors of high-resolution dots. With the spot color printing process, only one color needs to be printed, and it is not easy to get dirty on the back. Using the four-color printing process, some parts of the graphic may be synthesized by several colors. With the spot color printing process, only one color is printed on the corresponding part, which avoids the possibility of overprinting errors.

3. What issues should be considered when arranging the color sequence of a monochrome machine?

(l) The principle in favor of registration. During the printing process, the paper generally stretches due to water absorption, and also stretches under the action of printing pressure and peeling tension, especially when printing the first color, which causes the first color to be the most difficult and the color to be printed later. Accurate, so the first color should be printed first with colors that do not require high registration.

(2) The principle is conducive to color change. The light ink is printed first, and the dark ink is printed later, so that it is easier to clean the inking unit.

(3) The principle of importance of color. Placing important colors on the back for better color rendering and easier gray balance control. For prints with warm tones, such as pictures of characters, it is better to print magenta and yellow later; for prints with cool colors, such as glaciers, snow scenes, landscape paintings, etc., it is better to print cyan afterward.

(4) The principle of first small and then large inked area. First print the color with a small ink area, and then print the color with a large ink area, so as to prevent the first ink from being scratched when the paper is fed and printed again. When printing a large solid area, if the paper is thin, paper curling may occur; in order to prevent the back side from smearing, powder spraying may also be required. These reasons require large areas of solid color to be postprinted.

(5) The transparency of the ink determines the color sequence. Generally, the one with the worst transparency is printed first, and the one with better transparency is printed later.

(6) The brightness of the overprint color determines the color sequence. Generally, dark colors are printed first, followed by bright colors.

(7) If there is a flat screen and solid color overlap on the printed matter, first print the flat screen, and then print the solid color, and the overprinted ink color is more flat.