1. The type of resolution of plexiglass screen printing
Several different resolutions are used in the scan input and print output of image processing. Resolution refers to the maximum number of parallel points and lines that can be distinguished in the unit length per unit length.
There are generally four resolutions used:
1. Scan resolution Spi (sample / inch): resolution. It is used by scanners and digital cameras.
2. Display resolution PPi (pixels / inch): It is the number of graphics and text, and the number of pixels.
3. Printing resolution Dpi (character points / inch): the resolution of the printer output.
4. Print copy image resolution LPi (number of lines / inch): resolution of screen line number, line frequency and halftone of image copy. For common resolutions, Dpi is used instead of Spi and PPi.
Second, the type of resolution of plexiglass screen printing
(1) Scanning resolution (input resolution):
The gray scale resolution of the scanner is generally explained in the manual. Refers to the amount of information acquired by the scanner on each inch (cm) original image. It is limited by the maximum optical resolution or interpolation resolution the scanner has.
1. Optical resolution: It represents the highest input resolution (also called physical resolution) that the scanner's own optical system can achieve. It is divided into horizontal resolution and vertical resolution, which refers to the true resolution of the scanner (CCD).
(1) Horizontal resolution: The true resolution of the optical system CCD, also known as optical resolution. Such as 300-600Dpi, 600-1200Dpi, 1000-2000Dpi, high-grade up to 4000-8000Dpi.
(2) Vertical resolution Dpi refers to the number of steps per inch that the stepper motor can move in the mechanical design of the scanner, which is related to the mechanical transmission part. Vertical resolution is not as important as horizontal resolution.
2. Maximum resolution (interpolation resolution): refers to the maximum resolution of the scanner calculated by software interpolation after scanning by optical resolution. Usually 2-4 times higher than the optical resolution. This resolution does not guarantee image quality.
3. Image resolution: refers to the amount of information stored in an image, generally determined by the number of pixels (Pi × ei) in the horizontal and vertical directions of the image. If the resolution is 640-480, it means that there are 640 pixels in the horizontal direction of the image. There are 480 pixels in the vertical direction. The larger the value, the more pixels, the clearer the image. Some people think that the higher the resolution of the image, the better. Although it makes sense, it is not practical. Because the human eye's recognizing ability can not see the nuances of the image at a certain distance. If an image is printed with 600Dpi and 1000Dpi resolution at the same time, the result quality is the same. Therefore, it is not necessary to set the resolution too large, because the increase in the amount of information wastes time. However, the resolution cannot be too small, otherwise the layers will be lost and the image restoration will be difficult.
4. Monitor resolution: the total amount of information that can be displayed on the computer screen at one time. Refers to the number of dots per inch on the monitor in the horizontal direction. Common monitor screens are 14 ", 15", 17 ", and 19". There are three types of display resolutions: 640 × 640, 800 × 600, and 1024 × 768. The large screen display has high resolution. The size of the display resolution will only affect the convenience of the end user when working with the image, and will not affect the output quality of the image data.
(2) Output resolution:
Output resolution: only used for printer output and printing jobs, it represents the number of pixels per inch (Ppi or Dpi) required for the final document to be sent to the laser imagesetter or printer. Comprehensive settings such as copy method, screen convention, and resolution of the output device determine the exact output resolution of the image.
Printer resolution: used to measure the number of dots per inch that the output device can produce in the horizontal and vertical directions. The higher the resolution of the printer (laser imagesetter), the finer the dots produced, and the more continuous the image tone. The resolution of the printer limits the maximum number of single colors that the printer can reproduce.
3. The relationship between input resolution and output resolution
1. Input resolution: the relationship between Dpi and Lpi Dpi> Lpi half times
Relationship between input resolution (scanning resolution) and output resolution (recording resolution)
Input resolution = number of recording lines (Lpi output image maximum side length (inch) / input image maximum side length (inch) × 2
The scanning resolution is twice the number of screen lines, such as the original scanning setting of 80 lines / inch is 150-200Dpi.
2. Output resolution: ten to twenty times of Dpi> Lpi
The gray scale value output by the imagesetter is directly proportional to the resolution Dpi of the imagesetter and inversely proportional to the number of screen lines Lpi.
Gray level = output resolution Dpi (2 + 1) / number of image screen lines Lpi
Such as electrical sub-scanning 10 × 10, 16 × 16 pixels or more (electrical extension 23 × 23 scans a dot). If the imagesetter output film, the original line number is 50-100 lines / inch, 1200Dpi should be set on the imagesetter.
If the gray level of the output image is required to be 256bit, the output resolution of the recorder (scanner) should be set to more than 2500Dpi to achieve the screen line number of 150 lines / inch.
4. Conversion of resolution formula of plexiglass screen printing
Best image resolution = 2 × screening line scan resolution = N × image optimal resolution (N stands for zoom ratio) Color manuscript scanning resolution = screening line × 2 × magnification Example: enlarge the original size by 2 times The number of screen lines is 150DPi, and the set scanning resolution should be = 2 × 2 × 150 = 600DPi.
Ningbo Yinzhou Hengxi Winbate Household Product Manufacturer , https://www.nbwinbate.com