How to get a high-quality image scanning effect

Consumers have higher and higher requirements on the quality of printed materials, especially color images. However, the quality of color images printed by some magazines and magazines is still not high and the color distortion is serious. Practice has proved that scanning color separation technology is the key to the quality of color image replication. Image scanning requires a reasonable setting of the scanner's resolution, scanning brightness, hue and other parameters. Otherwise, it may cause a lot of loss of image details, color cast, black and white fields are unknown and so on. Even the post-processing and adjustment will only further aggravate the image loss, and it will not be able to obtain similar effects with real objects. Therefore, before scanning, it is necessary to establish a correct scanning concept and clarify the basic process of image scanning. Only in this way can high-quality images be scanned.

Image scanning is both technical and artistic. According to different types of manuscripts, rationally set and adjust parameters such as gray balance, tone contrast, color correction and sharpness, and then use aesthetics to deal with the color tone, saturation, spatial distance, light and shade, light and shadow changes. To improve the image quality of color prints, we must do a good job in the process of scanning and color separation, and train operators with higher levels.

Scanning the original directly affects the quality of the scanned image. When selecting an original, see if the surface of the original is scratched, dirty, whether the characters and lines are complete, whether there are missing pens, or broken pictures. Second, see if the picture is color cast. Under natural light or standard light sources close to daylight, observe whether the white, gray, black, or other achromats are disturbed by other colors. Three to see if the main color is accurate. Reflected drafts (such as photos, etc.) are slightly more colorful than the actual scene. For people-oriented reflection drafts, the color of facial skin should be the standard. Fourth, see if the contrast is moderate. The contrast of the reflection draft includes luminance difference, color contrast and contrast balance. The brightness difference is moderate, there are rich transitions in the high-profile and dark-sounding parts; the color contrast is moderate, the reflected draft color concentration is large, and it has a strong three-dimensional sense; the contrast is good, and the same color has the same color performance in the high-key and dark tone parts.

In order to avoid the inconvenience caused by the difference between the screen display effect and the actual print, before the image scanning is performed, the display brightness, display color, and other parameters of the display should be adjusted so as to be consistent with or slightly higher than the parameters set by the scanner. . Place the original in the scanner's optimal scanning area and set all the scanner's controls to automatic or default. Open the scanned image of the sample in Photoshop and use the "Image → Adjustments → Hue Homage Command" to see which cracks, streaks, and dark spots are visible.

When dealing with scanned images, many designers often use professional image software to rotate the image. This not only wastes time but also reduces image quality. The protractor should be used to measure the precise angle at which the original is rotated, and the original is scanned obliquely for high-quality images.

Choosing the right type of scan will help improve the scanner's recognition success rate, as well as generate files of the right size. Usually, the scanner provides users with three types of scans: color, grayscale, and black and white. It is properly selected according to the scan object and application before scanning. The "color" type is suitable for scanning color photographs. The red, green, and blue channels have to be sampled and stored at multiple levels. This method produces larger size files; the "grayscale" type is often used for both existing and textual texts. The sample text and manuscripts are mixed, and the file size is of a moderate size. The “black and white” type often scans black and white originals. The scanner displays two black and white pixels according to one bit, and the size of the generated file is the smallest.

For a color image, it is best to use a color scan. In this way, various adjustments can be made to the manuscript, the amount of scanned color information is large, the scanned color is more saturated, and the levels are more abundant; then, using Photoshop, the color image is converted to a grayscale image. In theory, the higher the resolution of the scanner is set, the more pixels per inch of scanned image are, and the richer the details of the expressed manuscript are. Because the highest resolution of the scanner is obtained by interpolation, scanning with accuracy beyond the optical resolution of the scanner will not only help the output but will increase the file storage and reduce the work efficiency.

When scanning a drawing or an image containing text information, the scanning resolution should be set higher, so that each line stroke can be better distinguished; if the scanned image is just a screen display or a web page image, the scanning resolution can be set to 72 dpi. It facilitates the transmission of images on the Internet; if the images are to be printed and published, a resolution of more than 300dpi is required.

Before the formal scan, prescan is necessary. Prescan has two advantages: First, it can directly determine the area that needs to be scanned, cuts and rotates the image, and reduces the image processing after the scan. Second, it observes the prescan. After the image, you can see the color of the image. If you are not satisfied, you can readjust the scan parameters.