When using Photoshop to restore images, the Eraser Stamp tool is one of the most convenient and commonly used tools. It can easily clone the image information of other parts to the areas with pixel damage or pixel loss. To create a more natural and perfect restoration effect, when using the eraser stamp tool, the options of the eraser stamp tool should be strictly set.
First of all, when using the eraser stamp tool to restore an image, an appropriate clone source point should be selected. Of course, the clone source points should be free from damage and dust, but more importantly, the pixels of the clone source points should be able to match well with the pixels around the spots; otherwise, if the repair marks are too obvious, it will affect the overall effect of the image.
Secondly, choosing the right brush when using the eraser stamp tool is also quite important. In general dust correction, the selected brush radius should be slightly larger than that of most spots so that the spots can be covered in one stroke during the modification process. When choosing the hardness of a brush, on the one hand, it is necessary to ensure that the brush has a good function of covering damage in one stroke; on the other hand, it is also necessary to ensure that the copied content can blend well with the surrounding pixels. Therefore, the hardness of the brush is generally set between 75% and 95%. If the color gradation around the spot to be covered is rich, the hardness of the brush should be set lower. When the color gradation around the spot is relatively single, the hardness of the brush should be set higher. When setting the brush spacing, it is generally advisable to set it at 1%.
Secondly, when using the eraser stamp tool, the normal mode is generally selected. Meanwhile, to better cover the spots in the image, the opacity is generally greater than 80%. And to facilitate the restoration of multi-layer images, it is usually necessary to set the "Alignment" and "For All Layers" options in the eraser stamp tool. Through these options, the multi-layer restoration of images can be conveniently achieved.
Finally, it is necessary to emphasize that before correction, the image should be enlarged first, usually to the extent that the pixels or jagged edges of the image can be clearly seen. In this way, during the repair process, it is very easy to determine whether the copied part can blend well with the surrounding parts.
"Dust and Scratches" filter
The "Dust and Scratches" filter can identify defects in an image and then reduce dust and wear in the image by fusing the pixels around the defects. It is particularly suitable for situations where the damaged part has a strong contrast with the background image, such as very bright (or very dark) damage on a dark (or bright) background.
When using the "Dust and Scratches" filter, you should first select the area to be corrected or copy the area to be corrected onto a new layer, and then eliminate the dust defects in the image by changing the radius value and threshold in the "Dust and Scratches" filter panel.
The radius option in the "Dust and Scratches" filter dialog box is used to set the size of the pixel range that can be defined as defects, with a value range of 1 to 100. The larger the radius value is set, the wider the pixel range of defect fusion will be when using this filter; conversely, the narrower the pixel range of defect fusion will be. The size of the radius value is generally determined by the resolution of the image and the damage radius. When the resolution of the image is large or the damage radius in the image is large, a larger radius value should be set; conversely, a smaller radius value can be set. As shown in Figure 2, the "Dust and Scratches" filter is used to correct the gray background of the image. When the radius is set to 10 and the threshold is set to 10, due to the large damage radius in the image background, there are still relatively obvious damages and spots in the image. When the threshold remains unchanged and the radius is set at 30, the damage and spots in the image background are improved to a considerable extent. When the threshold remains unchanged and the radius is set at 50, the improvement effect on the image background is better.
The threshold option in the "Dust and Scratches" filter dialog box is used to set the degree of pixel difference in the defect area that can be detected, with a value range of 0 to 255.
When the threshold is 0, all pixels in the selected area or image will be detected and all will be identified as defects. When the threshold is 255, there are almost no detected pixels in the selected area or image, and the "Dust and scratch" filter has almost no corrective effect on the image. Therefore, when the contrast between the defect and the surrounding pixels is large, the threshold should be set smaller to allow the defect to fuse more surrounding pixels, thereby reducing the contrast between the defect and the surrounding pixels to a greater extent. Conversely, the threshold should be set larger. The threshold is usually set between 0 and 128. As shown in Figure 3, when the radius is 50, the smaller the threshold, the stronger the softening effect of the filter on the background details of the image. When the threshold is set to 5, a better correction effect is achieved for the image background.
Under normal circumstances, when using the "Dust and Scratch" filter, the appropriate radius value should first be determined based on the resolution of the image and the damage radius. Then, a more optimal threshold should be further set under the determined radius value. This way, on the one hand, it can significantly improve the original defects of the image, and on the other hand, it can also maintain the original style of the image as much as possible.
