Small Paper Boxes With Lids Basic Knowledge Of Printing Process: Printing Basic Elements Dot

Small Paper Boxes With Lids Basic knowledge of printing process: printing basic elements dot

 

The principle, characteristic and application of dot. The following content is applicable to offset printing, part of the content can also be used as a reference for other types of printing, in the future when talking about specific printing types, will do one by one explanation. As this series of articles is for the design, color separation output personnel tutorial, not printing professional discussion, some principles and algorithms are only briefly explained, not in-depth discussion.

 

In conventional printing, the dot is the basic printing unit of the printed image. The print can reproduce the continuous tone by comparing the image unit with the blank.

 

The graphic information and color shading of printed matter are composed of different hues and different lightness by superimposing various dots of different sizes in the printing process. This kind of text and text formed by the dot is called "screen" in printing. Screen is originally a kind of screen in a traditional sense of "screen" used in photographic plate. When used, the screen is installed in front of or above the photoreceptor, to divide the incident light when shooting, and form different size dot corresponding to the color intensity of the original manuscript on the photoreceptor. The commonly used screen early for glass screen, later developed into contact screen. Now the new electronic color separation machine or color desktop publishing system, has no screen for screening.

 

In the method of amplitude-modulation meshing, photographic plate making is using the traditional screen equipment. The hanging method of the electronic color separation machine IS generally developed by the German Hell company IS (Irrational Tangent Screening) dot technology (non-tangent Tangent Screening) and RT (Rational Tangent Screening) dot technology (tangent tangent). Color desktop publishing system uses PostScript network technology.

 

Dot is the most basic element in printing process. There is always a certain limit in the order of screening, the level change of the image can not be achieved as the continuous modulation image stepless change, so the screening image is called halftone image.

 

Dot is the basis of printing and reproduction process, is the most basic unit of text and text, the role of dot is mainly:

1) The printing effect is responsible for the task of hue, brightness and saturation;

 

2) is the smallest unit of lipid-sensing and water-repellent, and is the basic element of image transmission;

 

3) In color composition, it is the organizer of image colors, layers and Outlines.

 

First, the size of the dot

The traditional half-tone image (generally formed by the amplitude modulation dot relative to the frequency modulation network) is arranged by the dot with different sizes and the same distance (dot center distance), forming a continuous visual feeling, to achieve the purpose of reproduction. Among them, the regular arrangement of nodes are diffused from the center, so the number of network cables formed by the arrangement of nodes determines the size of a single dot area.

 

Dot size is determined by dot coverage, also known as inking rate. It is customary to use "success" as the unit of measurement. For example, the network with 10% coverage is called "ten percent network", the network with 50% coverage is called "fifty percent network", the network with 0% coverage (i.e. no network) is called "no network", and the network with 100% coverage is called "on the spot".

 

The number of network cables is initially defined according to the number of lines on the screen. The more network cables, the higher the fineness. The common number of adding network cables is 80lpi, 100lpi, 120lpi, 133lpi, 150lpi, 175lpi, and 200lpi. The number of network cables per square inch. It is also possible to calculate the number of dots per square inch, which is equal to the number of network cables squared.

 

The following is an example to calculate the size of the actual dot points, assuming that the area of the space occupied by a single dot is S, the specific area of the dot points is M, the number of network cables is L, and the dot coverage rate is n%, then:

 

M=S×n%=2.54cm×2.54cm/ (L×L) ×n% This formula yields an area in square centimeters.

For example, 50% of the 200-line dot point size is:

 

2.54 x 2.54/(200 x 200) x 0.5=0.000080645cm2 = 0.0080645mm2

 

The dot diameter is about 0.09mm

The tone of printed matter is generally divided into three levels: light tone, middle tone and dark tone. Brightening part of the dot coverage is about 1 ~ 3; The dot coverage rate of the middle part is about 4 ~ 6 percent; The dark part is 7 ~ 90 percent. There are also the off-net and field sections.