Presswork site ABC

Pressworking in the process, mediate half-tone image is undertaken adjustment expression by the density of the site continuously. And mix through the site CMYK4 color, can show boundless much color.
Pressworking at present the site that uses in craft basically has two kinds of different kinds: Amplitude modulation site (AM) with frequency modulation site (FM) .

Amplitude modulation site is a kind of most extensive site that uses at present. Its site density is fixed, will behave colorific depth through adjusting the volume of the site, realized tonal transition thereby. In presswork, the use of amplitude modulation site basically needs to consider the factor such as precision of angle of site size, screen dot shape, site, reticle.

Site size

The picture is as follows:

Site size is pass a site cover rate decision, also weighing Chinese ink rate. General customarily likes to serve as into ” with “ measure an unit, for instance 10 ％ enclothe the site of rate to call “ to become site ” , enclothe the site that leads 20 ％ to call “ 2 into site ” additional, enclothe the site that leads 0 ％ to call “ absolutely net ” , enclothe the site that leads 100 ％ to call “ on-the-spot ” .
The rank attune of presswork differentiates commonly for 3 administrative levels: Highlight, middle tone, shadow. The site of highlight part is enclothed rate for 10 ％～ 30 ％ are controlled; The site of middle tone part is enclothed rate for 40 ％～ 60 ％ are controlled; Shadow part is 70 ％～ 90 ％ . Absolutely net and on-the-spot part differentiate additionally.

Screen dot shape
The screen dot shape in pressworking is everybody not merely in the imagination only circle a kind, wear with 50 ％ the figure that place of the site below case of Chinese ink rate shows will differentiate, can divide for: Quadrate, circle, lozenge 3 kinds.

Quadrate site is enclothed in 50 ％ below rate, into chessboard shape. Its grain is keener, very strong to the expressional ability of administrative levels. Suit line, graph and the expression of a few firm tone image.
No matter circular site is to be below highlight or the case that the inter moves, independence is between the site, only the ability below the circumstance of shadow has a part to be linked together. So to the expressional capability that gathers administrative levels not beautiful, 4 kinds in pressworking use lesser.
Lozenge site is integrated the soft tone of the site of hard harmonic circle of quadrate site is characteristic, colour transfers natural, suit the expression of general picture, photograph.
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