resolution ratio

Mouse resolution (dpi) refers to the positioning accuracy of the mouse, and the unit is DPI or cpi, which refers to the maximum information that can be accurately positioned every inch when the mouse moves.

DPI was originally a recording unit in printing, indicating the number of dots that can be printed per inch. However, with the rapid development of digital input and output devices, most people also use DPI to represent the resolution of digital images. However, more rigorous people may notice that the dots calculated during printing are different from the pixels displayed on the computer monitor, so more professional people will use PPI (pixels per inch) to represent the resolution of digital images to distinguish them.

What is the resolution of the printer we usually talk about now? It refers to the number of "theoretical" dots that can be printed per inch in the highest resolution mode of the printer.

Most optical mice have a resolution of 400 DPI (dots per inch), which means that if there is no software compensation, the cursor will move 400 pixels on the screen for every inch the mouse moves on the desktop.

(Most optical mice have a resolution of 400DPI, which means that when the mouse moves 1 inch on the desktop, its pointer will move 400 pixels on the screen without software compensation.

A more reasonable explanation for dpi is this:

If the resolution of a printer is 4800× 1200dpi, it means that the nearest distance between two ink dots in the X direction (horizontal direction) can reach 1/4800 inches; In the Y direction (longitudinal direction), the distance between two ink dots can reach11200 inches.

In addition, in general, we think it is meaningless to print images with higher printing accuracy (such as 4800X 1200DPI) above 600x600DPI on ordinary paper.

For example, at present, the highest nominal resolution of HP inkjet printer is 4800× 1200dpi, that is to say, in the X direction (horizontal direction) of paper, 4800 ink dots can be placed per inch in theory. But what if you really put all 4800 ink dots on an inch of ordinary media? -The absorption of ink by paper is supersaturated, and the ink becomes one piece, which reduces the resolution. Therefore, the "theoretical" number of dots refers to the capacity limit that a printer can reach, but its realization depends on the cooperation of paper. If special paper is used, better performance can be achieved, and more independent ink dots can be placed per inch. If the paper does not support the selected highest resolution, the adjacent ink dots will merge into one piece, thus achieving the image printing effect.

Therefore, you may find that in the new HP DeskJet printer (such as HP DeskJet5550), if special paper is not selected, in order to ensure the printing effect, the printer will not print at the highest resolution.