Summary of pre heat issues VII

Overview of prepress problems (VII)

overprint, overprint, trapping, embossing

overprint: refers to the overlapping and registration of various color plates when printing in multi-color printing

trapping: it refers to that there should be a certain amount of staggered superposition at the junction of one color block and another color block to avoid exposing white edges during printing, so it is also called supplementary white exposure; The place where the two colors intersect may be offset in the printing without trapping, resulting in white edges or color aliasing. Trapping is to use the two colors at the intersection to penetrate each other a little, so that white edges will not be generated

imprinting and overprint mean the same thing, that is, one color block is overprinted on another color block. However, when printing, pay special attention to the overprint of black text on the color image. Don't hollow out the pattern under the black text, otherwise the black text will show the white edge when the overprint is not done

for example: the magnanimity of four P's is 16 Kai, which is made of PS, and the text is k100. Send it to the center of the sending film and tell it that the black words are not embossed, that is, the position of the black words is hollowed out on other color plates,

will cause inaccurate overprint and white exposure. In PS, the black text overprint is to change the layer mode of the black text layer to the positive film overlay bottom, so that the black text in other color plates is not hollowed out, so there will be no white exposure People who just enter the printing industry and like to use PS design must pay attention to this problem Besides, we must form the good habit of P reducing the workload of experimenters' calculation, s making base maps, CD or AI typing. In this way, the printed text will not have burrs

generally, black in CD and PM is the default impression

1. Should all bitmaps be overprinted or trapped? Because some customers directly gave us bitmap (some bitmaps are quite complex) files and output proofing, but they didn't find any inaccurate chromaticity

answer: no ~ ~ ~ overprint in certain cases, as long as k100 black or graphics can be

2 How thick should the line overprint be in order to register the color for film production and printing? Is a trace (0.01 mm) enough? How much does it cost to convert into Pt units

answer: very thin line ~ ~ that is, 0.2 points. 1pt=0.35146mm

3. Is the function and principle of overprint in CD and ill the same? It seems that I heard that the lines in ill are thick and thin at these temperatures, which is half of the lines, isn't it? What's it like on CD

answer: there is no such statement

4. Overprint in ill and disposal of standard changes: is it safer than CD

answer: do it in the normal way. Software is just a tool, there is no better or safer

5 Spot color overprint, spot color and black, special, black, is it overprint with lines? Spot color and black, special, black, is it filled with Overprint? If we want to prevent the abnormal pattern caused by "two kinds of black", can we only use line overprint? Or is there any other way? Or is it possible to register the color without overprint? Is spot color transparent? Then the spot color can't be filled and overprinted with the spot color, but can only be overprinted with lines

answer: Line overprint is relatively better

6. Suppose some kind of overprint

suppose in ill, a pattern with red fill in the middle and green outline lines, and green fill in the bottom, can line overprint be done (green outline lines on the same layer as red, and green fill in the bottom, as overprint)

answer: no overprint. Normal output can be

7 If it's just CMYK, the pattern is similar to the color inserts in cartoon king, or the cartoon cartoons in cat and mouse, the animated characters have black lines to indicate their outlines. Do you also need to overprint such a complex picture? It's hard to imagine a color block, a color block to overprint?! If there is no overprint, how are those animation magazines printed

answer: that's the same sentence. Normally, only black is used for overprint, and other colors are output normally

8. If the black outline line on the drawing given to me by others is made by "leaking black" (for example, there is a seam between a red and a green, and there is a black below the seam), is this kind of drawing "you can only cross it yourself and make overprint again", is this too sad

answer: there is a black under the seam to make overprint

in fact, overprint is very simple, Just remember one thing: generally, only black words or black graphics are overprinted, and other colors default to normal output ~

if it is a printing car with a few million sets like Heidelberg, there is no overprint problem at all, but according to the national conditions, many printing factory owners do not have such good equipment now, so there is a phenomenon that the printing car is inaccurate and needs overprint

when overprinting strokes, we usually rely on experience. Large area filling strokes should be set a little thicker, 0.1~0.2mm is appropriate, and small area filling strokes should be relatively thin. When you use a magnifying glass to observe the printed matter after the strokes are folded, sometimes you will find that the strokes turn black. There is no way