Printing FAQ (18-21)

18. What are the commonly used output devices? What are the areas of application?

A: The designed page electronic file can be output by the following devices:

1. Black and white laser printer: used to print black and white proofs or final black and white official drafts.

2. Color laser printers: used to print color effect drafts or final color official drafts.

3. Color inkjet printer: used to print color effects.

4. Color large-format inkjet printer: used to print large-scale color effects or final color official drafts.

5. Digital proofer: used to check the content of the page, the effect of color.

6. Laser Phototypesetting Machine: Used to output the film used for printing.

7. Direct platemaker: Used to output printing plates.

8. Digital presses: Output directly from electronic pages. No film or plate is required.

19, what type of scanner? What's the difference?

A: There are two types of scanners: one is a roller scanner; the other is a flatbed scanner that can be divided into high-end professional scanners and middle- and low-range flatbed scanners. The roller scanner is developed from the electronic color separation machine. Its sensing technology is a photomultiplier tube. Figure 5-1 shows the working principle of the roller scanner. The flatbed scanner is a CCD device to complete the scan. Different operating principles determine the difference in performance of the two scanners:

(1) The highest density range is different: The highest density of the roller scanner can reach 4.0, while the average mid-to-low range scanner has only about 3.0. Thus the drum scanner can sweep out more details in the darker areas and increase the contrast of the image.

(2) Different image sharpness: The roller scanner has four photomultiplier tubes: three for color separation (red, green, and blue) and one for a false light mask. It can make unclear objects clearer and improve the clarity of the image, while the CCD does not have the function of this main surface.

(3) The degree of image detail is different: After the image is scanned with a photomultiplier tube, the details are clear, the dots are fine, and the texture is small. However, the quality of the image scanned by the flatbed scanner is relatively poor in the fineness of the image. some.

20. What is Pantone? Why use Pantone to set colors?

A: Pantone is a famous American ink brand and has become a standard for printing color. It has made all the inks produced by it into the chromatogram and color standard. Pantone's color standard has become a recognized language for color communication. Users need a certain color and they can calibrate according to the color standard. Due to the wide use of the Pantone color standard, computer design software has a Pantone color library and uses it for color definition. When using the Pantone library to set the colors, the selection method is Pantone. However, it should be noted that most Pantone colors are spot colors. If you want to use four colors, you should set the color type to primary color. Figure 1-13 is an interface that defines the Pantone color.

21. What is color separation? Is separation important? How to color separation in Photoshop?

Answer: Color separation is a printing professional term, referring to the decomposition of various colors on the original into yellow, magenta, cyan, and black. The color separation works in computer printing design or graphic design image software. That is, the color mode of the scanned image or other source image is converted to the CMYK mode.

The general scanned image is in RGB mode, and the image taken with a digital camera is also in RGB mode. Most of the images downloaded from the Internet are also in RGB color mode. If it is to be printed, it must be separated into yellow, magenta, cyan and black colors. This is a requirement for printing. If the image color mode is RGB or Lab, there may be only dots on the K version when outputting, that is, the RIP interpretation only interprets the color information of the image as gray.

In Photoshop, the color separation operation is actually very simple: just convert the image color mode from RGB mode or Lab mode to CMYK mode. The specific operation is to perform Image/Mode/CMYK. The color of the image is thus represented by the colorant (ink) with 4 color channels. When the image is exported, the image will be generated from the color channel data and divided into yellow, magenta, cyan, and black four-color film films.