display resolution
The display resolution is the resolution of the display when the image is displayed. Resolution is measured by a point, and this "point" on the display refers to a pixel. The numerical value of display resolution refers to the number of horizontal pixels and vertical pixels on all visible areas of the whole display. For example, the resolution of 800×600 means that the whole screen displays 800 pixels horizontally and 600 pixels vertically. The total number of horizontal pixels and vertical pixels of display resolution is always proportional, generally 4:3, 5:4 or 8:5. Each display has its own highest resolution and can be compatible with other lower resolutions, so a display can be displayed with various resolutions. Although the higher the display resolution, the better, but also consider a factor, that is, whether the human eye can identify. For example, on a 14 inch display, the highest resolution is 1024×768, and 800×600 is the highest resolution that can be recognized by human eyes (we will call it the best resolution for the time being). Although the monitor can accurately display the image with the resolution of 1024×768, the human eye can no longer accurately recognize the screen information. On the same size screen, the higher the resolution, the smaller the display screen. Because the size of the display is large or small, and the resolution of the display represents the number of pixels in all visual ranges, the display effect of the same resolution is different on different displays, for example, the resolution of 800×600, and the display accuracy of 14 inch display is much higher than that of 17 inch display with the same resolution. For some good quality monitors (such as Philips 15A, 14A), 14 inch monitors can reach 1280× 1024, and 15 inch monitors can reach16000.
Print resolution
The printing resolution is directly related to the quality of the image or text output by the printer. Here we only consider the printing resolution of inkjet printers and laser printers. The printing resolution is expressed in dpi (dots per inch), that is, how many dots are printed per inch. The horizontal resolution and vertical resolution of inkjet and laser printing are usually the same. For example, when the printing resolution is 600dpi, it means that the printer can print 600 dots vertically and 600 dots horizontally in an area of one square inch, and a total of 360,000 dots can be printed. However, a 720dpi inkjet printer does not necessarily produce better print quality than a 600dpi laser printer. This is because every dot printed by inkjet printer is only approximately equal, and every dot will spread around before drying, which is not as uniform as that printed by laser printer.
scan resolution
There are three main factors that determine the scanner performance: scan resolution, the maximum number of pages scanned and the number of color bits. Scan resolution is the input resolution, while display resolution and print resolution are both output resolutions. We can adjust the scanning accuracy as needed when scanning graphics with a scanner, unlike fixed display resolution and printing resolution or only a few options. Scan resolution is also represented by dpi, but it doesn't have the vertical resolution and horizontal resolution of a printer, and the horizontal resolution of a scanner is half of the vertical resolution.
Scan resolution can be divided into optical resolution and interpolation resolution. Optical resolution is the actual number of points that the scanner reads the source image when scanning. The optical resolution of the scanner is generally between 300×600dpi and 1000×2000dpi. In addition, the resolution of some scanners is 1200× 1200dpi, and the accuracy of horizontal resolution is improved by using hardware functions. Interpolation resolution refers to the resolution formed by inserting some points on the basis of real scanning points. It is the maximum adjustable resolution when scanning an image, which is usually 4- 16 times of the optical resolution, with 4 times, 8 times and 16 times being the most common. For example, for a scanner with an optical resolution of 300×600dpi, the interpolation resolution can reach 4800×9600dpi. When buying a scanner, you should consider the optical resolution, not the interpolation resolution. After all, the interpolation resolution is a generated point, not a real scanning point. Although improving the resolution makes the image more detailed, the details will be different from the original graphics to some extent, which does not mean the authenticity of scanning. Although the optical resolution is small, it represents the real accuracy of scanning. The optical resolution of a scanner with an interpolation resolution of 4800dpi may be 300×600dpi or 600× 1200dpi, so be sure to make clear the optical resolution when choosing the fourth one. For graphics with low scanning requirements, the accuracy of 300dpi can be used. For graphics with high accuracy requirements, the accuracy above 600dpi is used.