How to set the resolution of the scanner

Today, scanners are very common image input devices. However, the average user still feels very confused about the scanner's resolution setting. Especially when preparing to scan color photos and print them out with a color printer, they often do not know how to set the right ones. Resolution. Sometimes, because the set resolution is too low, the scanned image will appear blurred due to the apparent loss of sharpness. However, if the resolution is set too high, the print quality will not be better, and at the same time, due to the The increase in its own size often results in a significant reduction in the overall work efficiency. The time for scanning, image processing, and printing may increase by several times or more. In addition, excessive file size can also result in a waste of storage space. What's more, when the hard disk space is used as a temporary storage and exhausted, the last unavoidable result is downtime. In this regard, the scanner technology experts of Shanghai Zhongjing Technology Co., Ltd. believe that when users have printing requirements, the most appropriate resolution setting for scanned images should be based on the lowest resolution that achieves the best print quality. Can improve the overall work efficiency, save the storage space while ensuring the best scanning and print quality.

Common misconceptions

How to set the correct scan resolution? Users often think that the resolution of the scanner is set according to the maximum print resolution of the printer. For example, to use a 600dpi printer, use 600dpi as the scanning resolution. Shanghai Zhongjing Science and Technology believes that this concept can only be implemented in two situations. Users can scan black and white lines or text documents in pure black and white mode or output using a true continuous tone output device. If users only use the common color inkjet or color laser printer output, this approach is very inappropriate. At present, even when a general-purpose platform scanner is used, models with a resolution of 240 Odpi have appeared on the market, and the print resolution of color inkjet printers is also competing to reach a new height of 2400dPi and 2880dpi. Using 2400dpi resolution to scan, I wonder if I would like to get the final image file? We can see from Table 1 that the use of 2400dpi to scan a 4 inch * 6 inch color photo, about 400MB of memory capacity, in fact, this is not an ordinary computer can handle, not to mention the improvement of print quality is not substantive s help.

Table 1, Relationship between Scanner Resolution and Document Size

Color scan image resolution setting

The most common color inkjet printers, laser printers, and wax printers are collectively referred to as discontinuous-tone printers. Each of the smallest dots they can print does not exhibit a full 24 bit color. Take the CMYK four-color printer as an example. Each is the smallest. Points can only play cyan, magenta, yellow, red, green, blue, black seven colors, plus no need to print the color of white, a total of eight colors. According to Shanghai Zhongjing Technology, users must first consider the resolution of the printer before deciding on the resolution of the scanned image. At this time, the user should be careful not to be misled by the manufacturer's pure promotional specifications. The standard print resolution of ultra-high-precision printers with resolutions of up to 2880 dpi and 2400 dpi on the market today should be 2880*720 dpi and 2400*1200 dpi, while the real resolution is actually 720 dpi or 1200 dpi. For color images for printing purposes, the user only needs to divide the printer's actual print resolution by 4 or 3 when setting the scan resolution. For example, for a 720 dpi resolution printer, the scan resolution can be set between 180 and 240 dpi. Sometimes, in order to get a clearer printing effect, the user simply sets the scanning resolution to high, but in fact, the result of this will not help the improvement of the printing quality, but only increases the memory of the computer in vain.

But is it 180dpi or 240dpi? If users can do some experiments, they can find the resolution that suits their printer more correctly (for example, the printer uses 720dpi). Choose a photo with high sharpness, color variety, and gradation. Divide the resolution of the printer by 720dpi by 4 and 3, which equals 180dpi and 240dpi. The user scans with the MICROTEK scanner with these two resolutions, and then prints. The effect is compared. If the user does not see the difference between the two images, 180dpi is enough for the printer, and the user can scan again with a lower scanning resolution (such as 160dpi). If the difference is still not visible, 160dpi is enough. . If the difference can be seen at a lower resolution, 180dpi is the best resolution. If you can see the difference between 180dpi and 240dpi, users should choose a higher resolution. If the user finds the most appropriate scanning resolution, the scanning resolution should be used when the scanner is used to print the scanned image in the future.

In addition to the resolution, the scaling factor is also very important in the scanning parameters, but most users do not understand its importance. The area of ​​the original is 4*3 inches. If the user wants to print with 10*8 inches, how should the resolution of the scanned image be set? The user should first set the resolution of the scanner to 180dpi according to the resolution of the printer (the printer still uses 720dpi as an example), and then determine the scaling ratio. For a 4*3 inch scanned document to be enlarged to 10*8 inches, the user should divide the target size by the document size, width: 10/4=2, 5=250%, and height: 8/3=2.67=267 %, the correct scaling should be set to 25O%. When the length and width scales are different, the user should take a smaller value to ensure that the printer's maximum print area is not exceeded.

At first glance, the scanner's resolution setting is like a foggy look, making it impossible to start. However, as long as the user follows the above method and sets it correctly, it is believed that the user can easily get rich colorful images.