Printing a tip

·¢²¼Ê±¼ä£º2015/5/7

1, plate-making, manuscript to into green (C), magenta (M), yellow (Y) and black (K) four color, the color separation principle is what?
Answer: the color of artwork or color photographs, the number of colors on the picture there are thousands of kinds. For the tens of thousands of colors in a colored printing, it is almost impossible. Is used on printing four-color printing method. The original color decomposition first, divided into green (C), magenta (M), yellow (Y) and black (K) four colored version, and then press for color synthesis. The so-called "separation" is according to the principle of the subtractive method, using red, green, blue three color filter on different wavelengths of light of the characteristics of selective absorption, and the manuscript is decomposed into yellow, taste, green color. In the process of color separation, the colors of light that is absorbed by color filter is the complementary color of light color filter itself, so that in the film, black-and-white images of negative, and network, any node negative, the final copy, into all kinds of printing blocks. This is the earliest photographic color separation principle. Due to the development of printing technology, we can now through the prepress scanners will be original color separation, sampling and translated into digital information, it is using the same process method to decompose the original color same as red (R), green (G), blue (B) three color, and digitally, again by mathematical calculation with a computer and can turn numeric information into green (C), magenta (M), yellow (Y) and black (K) four color information.
 
2, why before printing images on the net?
Answer: because printing process determines the printing only USES the network reappearance of the original row level, figure if zoom in, you will find is composed of numerous branches of a size. We see the dot size, although different, but all the same size of space position, this is because the original image after once and network, the image segmentation into the arrangement of the countless rules, namely the continuous tone image information into discrete dot image information. The color of the network, the greater the performance, level more dark; Network is smaller, the more shallow color, the brighter the level of said. Each node has a fixed space position and size is determined by the add line number, for example, add dot mesh is 150 lpi, is on an inch length or width has 150 outlets. Network space location and dot size are two different concepts, such as C50 % on behalf of the meaning of the dot size is accounted for 50% of dot spatial location, 100% refers to the dot size covering all node space, namely the printing in the "field", and 0% with no branches, only network spatial location, so this place, there is no ink is printed on. Obviously hanging mesh number, the greater the outlets of the smaller the space position, can describe the more level, more exquisite. In fact, the level of the manuscript and colour is to be reproduced by using the method of the net.
 
3, what is the density?
A: color object light phenomenon generally have transmission, reflection, selective absorption. As shown in figure 3-20 (color), O is color object, when the light of the incident light energy to Q, O the selective absorption of the object. Its transmission or reflection of light energy to Q. The density of the object O is: D = lg (Q/Q). Therefore said the objects absorb light density size of nature. Objects absorb large amount of light, its density is high, small amount of objects absorb light and its density is low. Density is a measure of film printing light transmittance, print color shades of a common physical quantities.
 
4, what is the printing image on the screen density? It with the image resolution, scanning resolution, laser phototypesetter is what kind of relationship between the output resolution?
Answer: because the print is composed of a network, so the printing image and screen density refers to the print in a horizontal or vertical direction per inch screen density, namely the net line number. Referred to as the screen density because the original print outlets have a line. Hanging is the number of network cable unit Line/Inch (Line/Inch), hereinafter referred to as LPI. For example, 150 lpi is refers to the Internet cable with 150 per inch. Give the image a net, hang the greater the number of mesh, mesh count, the more points the more densely populated, level expression more rich.
Because computer graphics is a lattice, is each pixel (the smallest unit of image is called pixels). Image resolution can be vividly interpreted as in horizontal or vertical direction, the unit length of a line by the number of pixels to describe, describe the line used by the more pixels, the higher resolution. Unit is generally Pixels of image resolution
PerInch (pixels per inch), usually expressed as PPI in English. For example an image resolution of 300 ppi, refer to it in a horizontal or vertical direction has 300 pixels per inch on; An image of a resolution of 720 I, refers to it in a horizontal or vertical direction has 72 pixels per inch.
Some equipment and the resolution of image resolution, just they are use point to express, it is expressed as the Dot Per
Inch, hereinafter referred to as DPI. As a resolution of 1200 dpi image scanner image input accuracy for can collect 1200 points per inch, or pixels. 3600 dpi graphic output precision of the laser phototypesetter for exposure to 3600 laser points per inch.
Image resolution PPI and LPI printing resolution (plus screen density) both connection and difference: image resolution is higher than the printing resolution, is generally more than 2 x 2 pixels to generate a network, namely the LPI is nearly half of the DPI.
 
5, what is color? Color separation is that important? How to color separation in Photoshop?
Answer: the color is a printing professional term, refers to the various colors of the manuscript is decomposed into yellow, magenta, blue and black four color color; In computer printing design or image software, color work is to scan images, or other sources of images of color mode is converted to CMYK mode.
General scan images for the RGB model, use digital camera image also to RGB mode, also mostly RGB image is downloaded over the network
Color mode. If you want to print, color separation, must be conducted into yellow, magenta, blue and black four colors, this is the requirement of printing. If the image color mode to RGB or Lab, output branches that may only K version, only when the RIP explanation interpreted the image color information as grey.
In Photoshop, color operation is very simple: only need to put the image color mode from RGB mode or Lab model can be converted to CMYK mode. Specific operation is to perform Image/Mode/CMYK. So the color of the image is represented by the pigment (ink), with 4 color channel. Images in the output when the film will be according to the color channel data generation network, and divided into yellow, magenta, blue and black four color separation films.
 
6, in colour separation, when the image from RGB to CMYK, the naked eye can see some color on the screen can produce significant change, what reason is this? What is the effect of image color?
A: in the image from the RGB color model to CMYK color mode, some images of some bright colors can produce significant change, this change sometimes can be clearly observed, usually by some the color of the bright colors are becoming dim. This is because the RGB
Color gamut than CMYK color gamut in bigger, that is to say, some can represent some color in RGB color mode after converted to CMYK, it is beyond the scope of the CMYK can express the color, the color can only be used similar color instead. Thus these colors create more obvious change. In fact, if you have color in the RGB color model images beyond the color Gamut, available Gamut Warning (color Gamut Warning) previewing.
 
7, design pattern with all the colors of the image which model is better?
Answer: in Photoshop, image color pattern with RGB mode, CMYK mode, GrayScale mode as well as other colors. For design image mode by ren yao to see images of end use. If the design of the image to print or printing on paper, best color with CMYK color mode, so that you see on the screen color and output print color or printing color is more close to. If the design is used in the electronic media display (such as web pages, computer projector, video, etc.), image color had better use RGB mode, because of the color of the RGB model more vivid, more rich, picture look good also. Channel is only three, and image data quantity is smaller, less amount of disk space. If the image is grey, then better with GrayScale mode, because even express image in RGB or CMYK color mode, still looks is a neutral grey color, but the disk space is much larger. Another gray image if you want to print, if use CMYK mode, according to the film and printing version 4, cost big, may also cause the gray balance control is bad for the press partial color problem, when there are large amount of color printing ink, can make the grey color images.
 
8 how, gold, silver printing? Prepress design have any requirements?
A: in design, customers often require use gold and silver printing, because the gold and silver cannot be implemented by four color color, so the printing and technology have special requirements. Printing, gold and silver is handled according to the color, with gold and silver ink to printing, so the film also should be the color film, separate out a piece of films, and sun printing alone.
In computer design, should define a color to represent the gold and silver, and define the type of the color for the color can meet the requirements of design. Due to the silver and gold and silver are opaque, so the design of gold and silver content setting of stamping (Overpint).
 
9, what is the color and the color printing? What is the color and the color printing?
A: color printing refers to the, not by printing C, M, Y, K four color synthesis of this kind of color, but in a specific ink to printing the color. The color ink is by printing mix well in advance or ink factory production. For each color print, has specialized in printing when a color version. Use the color can make the color more accurately. Although can't accurately according to color on the computer, but through a standard color matching system, color of sample card, can see the color in the paper on the accurate color, such as the Pantone color matching system will create a very detailed color sample card. To set in the design of non-standard color, the color printing factory is not necessarily accurately allocate, and also can't see the exact color on the screen, so if it is not special demand, do not have to use your own definition of the color easily.
 
10, 28 in typesetting and the graphic software why not set a resolution?
Answer: typesetting graphics software is object-oriented software, algorithm for text, graphics, are represented by language to express, the object is has nothing to do with the resolution, when they are in the output is the resolution of the output device to output, the output device resolution is high, the production page graphic output resolution is high. Therefore, graphics software and typesetting software don't have to set the resolution. In typesetting and the graphic software import images in the output is to read the original bitmap information, it's related to the resolution of the artwork.