How is the trapping method of desktop publishing software?

1. Trap processing of image processing software

The image processing software uses the dot matrix method to describe the "content information" to be expressed, and its trapping processing function is also implemented by a dot matrix method. There are two different ways of trapping using the dot matrix method. First, color blocks are used for the foreground and background colors. The computer analyzes all boundary pixels of the image and then selects the average value of all the pixels to complete trapping. The advantage of the trapping method is that the trapping processing speed is faster, but the printing overlay error is obvious; second, the foreground and the background color are continuously adjusted images. At this time, the trapping processing is usually set at both ends of the image boundary in advance. The trap width selects the middle color as the trapping color for each pair of adjacent pixels on the boundary, so that almost no border is seen on the printed matter.
2. Graphics Processing Software and Pattern Processing

Trapping in software

Graphics processing software and template processing software are based on the vector method to deal with trapping. The trapping vector processing method is a layout composed of vector graphics and text elements. The page description of this layout adopts a mathematically strict geometric description method, that is, using a straight line, a circle, and a cubic Bezier curve and its color filling to complete the pairing. Description of all profiled objects. The trapping process is based on the boundary between two different colors. The lighter side expands toward the darker side to form a new boundary line. This trapping method can better handle fine patterns and text trapping. Print, but bitmap color images cannot be processed.

Reproduced from: sina

Talk about trapping technology (white trapping) Collection This article by Rose Wei @ 2006-08-31 09:42 Clear Category: Prepress knowledge In plastic packaging and printing, white ink applications are quite extensive. Generally, in the printing of transparent or translucent plastic, it is necessary to make the bottom in white, and sometimes also to hold two layers of white. In order to prevent the white underneath the excellent block from being exposed due to overprinting, a white retraction should be considered before printing.

1. The white retraction can be performed according to the depth of the color or the customer's request. The retraction amount is generally 0.2-0.3mm.

2. If the color block is white and the side is transparent, white can be retracted to 0.3 mm.

3. Black and gold under the care of the white, the white can be retracted to black, gold 0.5-1mm.

4. If the color of the color block is light or flat, the amount of white retraction should be small or not retracted. For example, when the percentage of the dot of the color patch is between 30% and 50%, the amount of white retraction may be 0.15 mm; and when the percentage of the dot of the color patch is less than 30%, the white may not be retracted.

5. When whitening under the gradient pattern, white should be considered for oblique retraction. Under the cyan gradient, the color is white, and the cyan is dark where the white color shrinks by 0.2 mm, and the cyan color is where the white color shrinks by 0.1 mm. The inflection point shift method can be used now.

6. If the transparent color (no white ink under ink) is adjacent to other colors, the white color under other colors should be 0.2mm; if the transparent color is directly adjacent to the white, the white color should be extended to 0.2mm in the transparent color to avoid leaks. .

Reproduced from: bokewu.com