Printing platemaking process (2)

Fourth, what is a pixel? Resolution?
Pixels are the smallest unit that describes the image in a lattice. Although the pixel is the smallest unit describing the bitmap image, it has a fixed shape but does not have a fixed size. Resolution, representing an image processing device, to represent the fineness of images, prints.

Fifth, what is the color has nothing to do with the device?
The result of image color data obtained by a certain kind of image processing device should be able to be restored accordingly on another processing device.

What is color management? What are the contents of color management?
There is an interoperable problem between different software or hardware, how to obtain the expected consistent color under a variety of configuration possibilities, that is, study device-independent color representation, and the conversion of color representation for a specific output device. . There are three major aspects of color management: corrections, features, and transformations.

7. What is computer direct imaging printing?
Direct-imaging printing is a new type of computer typography printing technology. When coloring this kind of new technology, it does not require the process of traditionally printing the output film and then producing the PS version from the film. Instead, it uses a color desktop publishing system to edit graphics, photos, and text. After the images are processed in parallel, the images are directly presented on the printing plate for printing. The printing method achieves 1016 DPI resolution with up to 175 lines per inch quality color print.

8. What is the technical basis of the color desktop publishing system?
A graphical user interface (GUI) and "what you see is what you get" idea.
Second, the use of page description language Postscript.
Third, Macintosh computers and laser printers capable of outputting Postscript and typesetting software PageMaker use.

9. What is an open system?
Can accept any Chinese system input file, can be output to any English software for processing, the results can be sent to any kind of output device such as: electronic color machine, laser printer, laser imagesetter, computer It can also be output as a PS file, and can be exported to any output center in the world to output four-color CMYK color separation films. This is the concept of full openness. The Postscript language is the foundation.

X. What is the role of PostScrip? What are the characteristics?
effect:
PostScript language is an interface language output from the desktop system to the layout device. It is specially designed to describe images and text. A variety of desktop software systems work together and must rely on a certain format to exchange information with each other. This is the Postscript language.
The function is to record the image text on the page with a digital formula and run it on a computer. Finally, it is translated into a desired output by a Postscript decoder, such as being displayed on a screen or output on a printer or an imagesetter.
The Postscript file is just a text-based file that can be used on different computer workstations such as MAC, PC, NEXT, SUN, etc.
Features:
1) Comprehensive processing of text and images
2) The foundation for the openness of color desktop publishing systems: With the Postscript standard data format, data exchange between general-purpose computers produced by different manufacturers and various special computer systems is possible.
3) Avoid the dependence of layout on the use of equipment.

XI. What is the role of RIP?
The role of RIPR is to convert the lines, curves and images created in the Postscript application software into commands for bitmaps with the appropriate resolution, and to control the "yes" and "absences" of the laser spot output by the laser recorder as a switch. Output the formatted results to the film.

Twelve, what is OPI technology?
OPI is an annotation specification based on the Postscript language.
These annotations indicate the relevant geometric parameters of the high-resolution file, the location of the preservation and the parameters related to the communication network.
OPI can manage a large amount of image data in a centralized manner, generating a dedicated workstation with OPI annotations and display representations, and performing output management and image substitution functions, commonly called OPI servers.

13. What is the workflow of the color publishing system?
1) Text entry: Enter the text into the computer.
2) Scanning the image: The image is digitized and entered into the computer.
3) Group Edition: After editing and modifying the text and images on the computer, the text and images will be mixed, and the results will be printed out proof proofs.
4) Separation exposure: After raster image processor is used to describe the page description language of the layout into a bitmap image, the dot matrix image is sent to the laser imagesetter to control the sensitivity of the film.
5) Rinse: After the film is sensitized, use the punching machine (developer) to flush the color separation film out of the four-color film.
6) Print Proofing: Provide proofs and proofs for printing reference.
7) Finish color prepress processing.
If the material used for separation in the fourth step is PS (pre-sensitized plate), this workflow is called CTP.

XIV. What products are generally included in the product quality inspection before export?
How to adjust the imager's output characteristics?
What are the labels on the output film?
Pre-export quality inspection items:
1, before the output file inspection (laser proofs check)
2, check the layout and finished product size. Single-P or dual-P output problems and verifiable bleeding sites.
3, color map placement and cutting.
1) Check whether the figure is in a horizontal position, especially the visually obvious pictures such as the architectural building diagram, the connected map of Haitian, and the vast plain map.
2) Confirmation of the quality of the bottom of the picture: whether it is refunded according to the requirements, no leakage or retreat, and the retreat shall be sleek.
4, text confirmation: the correctness of the text to reach 100%. The text is big, clear, complete, clear, correct, and correct in color.
5, color blocks, color strip color confirmation.
6, picture blur and gradient quality confirmation
7, spot color sample and color sequence confirmation.
8, require the confirmation of the revised part.
Laser Imager Output Characteristics Adjustment:
* Imagesetter output is composed of halftone dots. The key to the calibration is that the size of the film internet point (ie, the concentration of the area dots) should be exactly the same as the dot size of the scanned image and the dot size specified in the application software.
* Tools: Density ruler, anti-reflectance instrument.
* Output exposure test: Objective To find an optimal exposure to set the exposure of the output machine to ensure that the imagesetter output can provide the necessary density without causing severe halftone errors.
* The method is: First use an image-setter to produce a page consisting of straight lines generated at different exposure intensities. After the page is developed, measure the exposure results with a density meter and select the best value.
* Whenever changing the important variables, such as table materials, liquid medicine, etc., should be tested once.
What are the labels on the output film: register marks, crop marks, adjustment bars, densitometer scale, file name, color name

15. What are the parts of the desktop of the tablet?
Consists of three parts, icons, windows, lai

16. What is the role and connection rules of the SCSI interface?
Role: Connect the edge of the computer and external devices, connection rules: address line is only 0-7, each device is connected in series, there must be a terminator at the end of SCSI

17. What is the difference between a stroked word and a lattice word?
Stroke words can be divided into POST, the way described by digital, can be arbitrarily zoomed in and out for the screen display, zoom will be deformed

18. What is a vector image and what is a bitmap?
The image is represented by a mathematical formula. Bitmap is represented by pixels

Production requirements: (based on the actual departure of film printing)
1. Determine the size of the finished product and the size of the left and right blank areas on the finished product:
If the above dimensions are incorrectly determined, you will have to face the fate of re-doing the whole task after investing a lot of time and energy in completing the work, because the workload of modification may be much greater than the amount of work to be done again;
2. Bleeding:
All future objects on the finished product close to the position of the cutting edge should be placed at least 3 mm beyond the cutting incision during production. After the future cutting, the effect of the object on the edge of the finished product will be correctly displayed; that is, the object (picture, graphics) A small part of the text, text, etc. will be cut off. This is called "bleeding."
3. Image format:
Pictures refer to images and graphics. Various types of pictures in computers are divided into two categories:
Image (also called raster image, bitmap, pixel map): refers to a picture composed of a pixel, the most common is the scanned photo, the image to use special image processing software to process the processing, such as PHOTOSHOP.
Graphics (also called vector graphics): It is composed of mathematical descriptions of diameters and curves. They do not exist by themselves. They are only created by specialized graphics processing software, such as those created by the drawing softwares such as FREEHAND, COREDRAW, and ILLUSTRATOR. Graphics are vector graphics.
The above two types of pictures are different in their essence. Please pay attention to understanding and distinguishing. The correct picture format should satisfy the following conditions: no loss of file information, small electronic file size, high efficiency when the film is separated from the film, and good versatility (acceptable by most output centers and application software). For images composed of pixels, the most common format is TIFF; for graphics, the most common format is EPS.
4. Image resolution and color space:
In order to achieve the effect of the printing level, the resolution of the image should be the number of screens printed at the time of printing.
1.5 ~ 2 times (refers to the 1:1 ratio, ie the picture should not be enlarged or reduced). For example, now the general color print is 175 lines/inch, then the size of the image (length and width cm) is determined, the resolution of the image should be 300DPI or 350DPI (number of 327 also need to take, take a multiple of 50 is better) After confirming, after installing the typesetting software, it is in principle required to no longer be able to zoom in or out. If it is absolutely unnecessary, it may be scaled from 10% to 20%. When the image is sent to the photocopy, it should be converted into CMYK color first. Do not use other color spaces such as RGB. All layers and channels should be removed when the image is stored last.
5. The size and color of the graphic:

The size of the graphics should be determined according to the size of the final printed product. Do not zoom in or out after placing the typesetting software (this will increase the time of photocopy output). The color of the graphics is generally marked with CMYK color (this can be expected to be true after printing colour).

6. Text:

If the text does not need special effects, it can't be printed out with image software such as PHOTO SHOP, and then it can be used as an image and then placed into the typesetting software (words printed in this way, the edges are imaginary); the text should generally be entered in the typesetting software, but also Typing in the graphics software, when the graphics containing the text are output in EPS format, select to convert the text into graphic selection items.

7. Registration issues:

Too small colored text or graphics (such as a thin horizontal line), if more than two colors of four primary colors need to be overprinted, blurring may occur because multiple color plates cannot be reprinted together 100%. Therefore, small text or graphics (including colored text, graphics, or colorless text, and graphics printed in two or more color backgrounds) should be as monochromatic as possible.

8. Overprinting and Trapping:

9. Submit documents before sending to the output center: (taking PAGEMAKER as an example).

(1) Place a graph in PAGE MAKER. When the graph is small (such as tens of K or less), it can be completely placed. That is, the graph is completely included in the PAGE MAKER file. The original image can be lost; but when the graph is relatively When large (such as a few hundred K, several tens of M, or hundreds of M), if the graphics are completely placed, the PAGE MAKER file will be too large to be manipulated and controlled, so when you put the image electronic size is greater than PAGE When MAKER sets the value, a query box appears: Do you include this graphic in PAGE MAKER? You should choose "No" at this time.

In this way, PAGE MAKER only places a low-resolution preview that is obtained from the original but smaller than the original image. You can manipulate this view. The position of the view completely represents the original image. This is called “Link. ".

(2) When PAGE MAKER encounters a picture when opening a file, it will search for the file's original location and search for the file; if it does not find it, it will search the current directory; if it still does not, it will display a message saying that the picture is not found. To! Select "Ignore", the page will still be the same, the pre-view is still, the file can be printed, but the figure