How much do you know about packaging offset? (3)

Under normal circumstances, when the intersection angle is 30 degrees, the pattern presented is more appropriate. Yellow and light colors because of poor color rendering, sometimes the intersection angle can be smaller.
In the four-color printing process, the dot of the object net is filled with four types of angles: 15 degrees, 45 degrees, 75 degrees, and 90 degrees. The main adjustment of the screen is 45 degrees, and the yellow is 90 degrees.
In spot-color printing, monochromatic lithography or monochromatic gradation superimposition of the field version, the gradation version is usually more beautiful with a 45-degree angle; two different-color gradation versions are superimposed, usually with 45 degrees and 90 degrees; Overprints of different color levels, usually 30 degrees, 60 degrees, and 90 degrees.
17. What effect does dot shape have on printing?
The shape of the dot is round, square, rectangular, brick, and it is determined according to the content of the manuscript when the color separation is screened. The network with different shapes has different effects on the printing and copying effect. Customary uses in the daily production are round and square dots.
The shape of the square dot network is relatively regular. With a small magnification magnifying glass, it can be seen that the ink is transferred in the printing process, and the printing quality is easily controlled. However, the square dot has the longest point at 50%, and the dot gain is also the most serious, which is likely to result in the loss of intermediate tone levels.
The circular dot also has a shape rule, and it is easy to determine the advantage of the dot transfer quality. The circular dot has the longest perimeter at 755, where the dot expansion is the most serious, and the dark high layer is easy to paste, while the mediation below the middle tone and the midtone tone is smaller and the level replication effect is better. Therefore, if the image of the original is dominated by intermodulation or high-profile, a circular dot should be adopted; if the original's picture focuses on the dark tone, a square dot should be used.
In short, the principle of choosing the dot shape is to minimize the loss of the gradation of the original theme part.
18. What is the tone and hierarchy?
The light and dark changes in the overall image of the printed matter are expressed as the overall tone of the image. The tone is overall speaking, and the overall tone changes from light to dark.
19. What are the ways to express hierarchy?
The methods used to express levels are usually continuous halo patterns such as photographs and halftone patterns such as prints.
20. What is Continuous Convergence Mesh Tuning?
Continuous tone means that the image of a picture is composed of very delicate dyes or pigment particles mixed in different proportions, and the color is in a continuous gradual state. For different compositions, the continuous tone of the artwork is composed of different particle density within the unit area.
The term "mesh tones" refers to the fact that the color change and depth change in printing are essentially discontinuous, and the change in color and tone is represented by the juxtaposition, superimposition, or half-and-half overlap of dots of different sizes. Since the pitch of the dots is smaller than the visual resolution of the human eye, the human eye will regard the halftone image composed of the colored mesh as a continuous layer change and color change, but if observed with a magnifying glass, only one particle can be seen. Dots of different sizes and colors can't see continuous changes in color and gradation, such as negatives used in printing and offset printing.
twenty one. What is high profile, midtones and shadow?
The bright part of the screen reflects a large amount of light and has a low density. If it is a halftone, the part with a dot size of 10% to 30% is usually called a high-profile part. The colored part on the screen has less reflected light and a higher density. If it is a halftone, the part with a dot size of 70%-90% is usually called a dark part. The portion of the screen centered on the degree of lightness and darkness, the amount of reflected light is between high-profile and dark-tone, and if it is a halftone, the portion with a dot size of 40% to 60% is usually called a midtone.
twenty two. What are the three primary colors?
According to the characteristics of physical stimuli of light, the visual physiological characteristics of human beings and the results of a large number of chromatic light mixing experiments show that the three monochromatic lights of red, green, and blue light are mixed in different proportions, and all other shades of light can be obtained. Neither can be obtained by mixing with any other color light, so red light green light and blue light are determined as light color primary colors. Since each trichromatic light has a relatively large wavelength in the visible spectrum, each specific wavelength has a correspondingly different color sensation for the human eye. In order to unify the understanding of the three primary colors, the International Commission on Illumination stipulates that standards The representative wavelengths of the colored primary colors are: red light 700 mm, green light 546.1 mm, and blue light 435.8 mm. (To be continued)