Scanning and finishing of prints

Printed matter is already screened, that is to say, it is composed of halftone dots. The dots of the print will interfere with the scanning process, resulting in moire stripes. And, printing webs, that is, those plum blossom patterns also affect the perfection of the scan results. This is especially noticeable when you look at it with 100% of the display. Moire fringes do not occur only during scanning. Moiré fringes may also occur in repetitive patterns such as fabrics. In addition, output techniques also affect them. Here we first talk about print scanning and striping problems.

First of all, the scanning itself can take some methods. For example, when you scan a print and you notice that the fringe is quite serious, you might consider scanning the print at an angle and then turning it in Photoshop. Photoshop produces an average effect when the image is turned, which helps to reduce the fringe interference. I suggest you try several more angles, and carefully observe their differences. Again, it is sometimes effective to scan for proper prints. Someone used coins to increase the print, of course, I mean a flatbed scanner.
In any case, when the image is swept into the computer, you must still further trim the image. Let's see what we can do next.

First, scan with twice the size of your desired image. First, this allows the image to have more data for you to edit, and reduces the loss of detail in the details of the finishing steps. Second, when you have trimmed this large image, it is reduced to the required size. The size of the image will be more delicate than that of the just trimmed and the interference fringes will be reduced.

Second, soften the image. First of all, it is recommended that you try to remove the moire using Filter>Noise>Despceckle. It doesn't always work, it depends on luck. Then, more importantly, is Filter>Blur>Gaussian Blur Gaussian Softening. Gaussian softening works at a level of 1/10 pixels. As for the degree of softening, it depends on the specific situation of the image. It is necessary to eliminate the moire fringe and not to lose the image detail too much. In general, the softness value will not exceed 2, and it is usually less than one. When doing this kind of work, advise you not to be too embarrassed, and do not forget that after the image is processed, when you reduce it to the required size, the phenomenon of streaks will be further reduced. In most cases, softening should be done in the most streaked color layer. I think the blue channel's interference is often the most serious, and it can make it more flexible. Of course, it is not only possible to select soft channels with soft interference, but also to soften different areas of the image. Because the stripes do not necessarily cover the entire screen evenly.

Third, when finishing and reducing the image, it is usually sharpened to enhance the clarity. Sometimes sharpening will make the stripes re-emphasizing. At this point, you need to sharpen the different areas of the image separately. As mentioned above, not only different areas can be controlled but also different channels can be handled separately.

Source: Saint Gerkan Design Print