1. The concept of four colors :
Normal four-color refers to normal four-color printing: that is, the printing process of using yellow, magenta, cyan primary color inks and black ink to copy various colors of color originals. Because the blue and blue are similar, the four colors have produced a popular saying in many places: black, red, blue and yellow. Four-color printing is also known as the CMYK printing method.
2. The concept of spot color printing :
Spot color refers to spot color printing, which refers to the printing process of copying the original color by using other color inks other than the four colors of yellow, magenta, cyan, and black ink.
3. The difference between spot color printing and four colors printing :
Spot color print blocks and four-color overprint blocks have different color visual effects.
The inks prepared by the spot color printing are obtained according to the mixing principle of the color reduction method, and the color brightness is low and the saturation is high: the spot color of the ink color is usually printed in the field, and the amount of ink is appropriately increased. When the thickness of the ink layer of the printing plate is large, the sensitivity of the change of the thickness of the ink layer to the color change is lowered, so that it is easier to obtain a uniform and thick printing effect.
The color blocks printed by the four-color printing process are composed of a certain proportion of dots, and the thickness of the ink layer must be strictly controlled when printing the dots, which is easy to change due to the thickness of the ink layer and printing. A change in process conditions causes a change in color intensity. Changes in the degree of expansion of outlets. This causes a color change. Moreover, since the change of any color constituting the color block causes the color of the color block to change, the chance of unevenness of the ink color will be multiplied, so the color block printed by the four-color printing process is not easy to obtain the ink color. Uniform effect. If you can't use the multicolor machine to overprint the color of the color block at a time. It is also easy to cause color shift due to the difficulty in controlling the color of the semi-finished product. In addition, the four-color printing is a combination of the subtractive color absorption and the additive color mixing of the dots, and the color block has a high brightness and a low saturation. For the light color block, a four-color printing process is adopted, and the ink has a low coverage, and the ink color is dull and lacks a thick feeling. Due to the angle of the dot, it is inevitable that people will feel the existence of the pattern.