Computer Graphic Design and Prepress Graphic Processing 500 Questions (42-47)

42. What are the characteristics of the PS font?

A: The PS font is a curved outline font described by Adobe's Postscript language. PS font is designed for PS device output, mainly used for laser printers and laser imagesetter output. Since the screen is not a PS device, the PS word is not used for screen display. Therefore, the PS word must be displayed in the corresponding dot font when it is used. PS font is the best print quality font, can be arbitrarily zoomed, printed clear and smooth. PS fonts are generally installed on a hard disk connected to a printer or imagesetter.

43. Why is it better to use a PS printer when printing proofs to customers?

A: The page interpretation language (PDL) used by the printer to interpret the pages. In addition to the Postscript language, most non-print professional printers use their own print languages, such as HP's PCL language. If you use ordinary non-PS printing to do proof printing, some errors in the production may not be found, especially the errors related to PS interpretation are not easy to find, which may result in loss of work. The page interpretation language and the final output language when printing using a PS printer are the same, and there is a problem that can be found as soon as possible.

44. What is RIP? Why do you like software RIP now?

A: RIP is an acronym for Raster Image Processing. It refers to a software or hardware card that interprets Postscript encoding as a bitmap image in a photo-memory system. It is generally called a raster image processor. It plays an important role in the color publishing system. Its function is to quickly interpret the prepared page as a command that can control the output of the laser recorder. It can automatically convert text, graphics, and images in the page. Into the digital lattice information, and then use these information to control the output device to record, so that its work is "off" or "on." The upgrading of hardware RIP requires complex processes and a long period of time, and cannot adapt to the rapid development of software technology. Software RIP is widely adopted because of its advantages of fast update, high processing quality, high speed, and display of post-processing results. RIP can drive multiple imagesetters at the same time, and the network function is strong.

45. What is color management?

A: Color management has two aspects: First, it is determined by the basic requirements of traditional color reproduction, that is, the basic settings and choices of the color reproduction characteristics determined according to paper, ink and other printing conditions, including tone reproduction, Gray balance and color correction, etc. The purpose is to adapt the separation and printing conditions. Gradation duplication refers to the correct setting of highlights, shadows, and midtones to accurately reflect the contrast of the original. This setting should be based on the characteristics of paper and ink, and has nothing to do with the display of the computer. The gray balance is determined by the specific paper, ink, and other printing conditions. Accurately determining the gray balance point facilitates accurate copying of all colors and prevents color shift. Color correction refers to a specific original color, and the CMYK printing ink is targeted for adjustment to obtain an accurate hue and sufficient color saturation. The other aspect of color management is based on automatic color management of a desktop publishing system or a graphic design system, that is, software calibration of the device, characterization of different color spaces, and coloring of different input/output devices. Pass to get the best color match.

46. ​​What is the purpose of color management?

A: The purpose of color management is to match the scanner to the scanner: to achieve color matching of different input devices, including various scanners, photoCDs, digital cameras, etc.; printer and printer matching: to achieve color matching between different output devices , including color copiers, digital proofers, fast (direct) printing; display and display, display and print matching: to achieve the consistency of the display of different displays, and to enable the display to accurately predict the output of the finished product; original and print matching: from Scan to output high quality color matching. Implements color management content embedded in the image file so that the image maintains color consistency regardless of the device being reproduced. See Figure 1.

47. What are the three elements of color management?

A: There are three important aspects of color management. It is also the three major elements of color management:

1 Calibration—adjusts the equipment according to the operating parameters of the equipment such as scanners, monitors, printers, etc.;

2 Characterization—Determines what the color range or reproducible colors of the input and output devices are, and establishes the corresponding characteristic parameter file, also called the device profile.

3Conversion—Transforms an image from the color space of one device to the color space of another device under known conditions. The purpose of the conversion is to make the colors seen on the screen and the final printed material as consistent as possible with the original. Since the color space of the print output device is smaller than the color space of the original, the color space is compressed and converted. Color space can be converted in a variety of ways: RGB to CMYK (scanner to printer), RGB to RGB (scanner to screen), CM YK to CMYK (a printer to another printer).

In this way, the relevant equipment has been calibrated and characterized accordingly. Based on this, the color conversion is performed according to the relevant data file to realize the color from the original input, computer display processing, and various color output. Consistent. (to be continued)