Scanning the Internet to make the picture more exciting (3)

3. Remove the texture of the picture by using the “draw off the net” method.

In PS, an image is actually composed of pixels with independent color information. As shown in the following figure, each small square is a pixel, which is the most basic element of a bitmap.

What we usually call "image resolution is 300 ppi (also called pixel per inch)" means that 300 pixels are arranged on an abscissa or ordinate in one inch.

If we reduce the image resolution of a picture from 300 ppi to 150 ppi, that is to say from 300 pixels per inch to 150 pixels per inch. We can simply understand that a pixel is removed from every two adjacent pixels to obtain a new image. But in fact, in this process, PS is to neutralize the color information of two adjacent pixels to form a new pixel, instead of directly removing a pixel directly; instead, increase the image resolution of the image. At the time, PS will calculate the color properties of the adjacent pixels and split the new pixel. This makes the picture's color transition relatively stable, while reducing or increasing the number of pixels while maintaining the same overall feeling of the original picture (this principle is called "auto-compensation" in PS).

PS's method of reducing image pixels can be visually understood as a combination of filtering and removing a part of pixels, which is conventionally called "pumping."

Similarly, we can also use this method to remove the number of screens in the scanned image, so as to achieve the purpose of removing the texture in the image.

If we want to get a 300ppi picture, we should set the scan resolution to 3~4 times the final result when scanning. Here we set it as 900ppi. The following figure is the 900ppi scanned image:

First, the picture resolution of this picture is reduced to two-thirds of the original picture resolution, ie 600 ppi (equivalent to rubbing every three pixel points into two new pixel points). Execute "image image size" in PS, call up the image size setting panel, and set the image resolution to 600ppi.

(to be continued)