Removing Dust and Scratches

The Dust & Scratches filter (choose Filter ’ Noise ’ Dust & Scratches) was created for the purpose of removing those ugly artifacts that are unavoidable when scanning old photos. With its Radius and Threshold sliders to help define edges, the Dust & Scratches filter is a powerful tool for eliminating a good deal of the unwanted debris from an image. If you re scanning a batch of old pictures from your grandmother s scrapbook, or that old team shot from your high school yearbook, Dust & Scratches works wonders. It can also help a great deal in getting rid of moir patterns that can appear when scanning printed halftones .

When using the Dust & Scratches filter, select small areas of similar texture in which to work. Each area of the image might require different settings. Applying it to the entire image all at once can result in a loss of detail. The Dust & Scratches filter has two controls, Radius and Threshold. Use the minimum Radius and Threshold you need to achieve the best results (as in Figure 19.2).

Figure 19.2: The area selected (left), and the filter applied (right)

Radius blurs, and Threshold restores . When you move the Radius slider to the right, you effectively blur the areas of most contrast. Move the Radius slider until the specks or scratch lines disappear, but do not overblur the image. Next, move the Threshold slider just enough to restore the surrounding texture but not enough to restore the specks.

Be cautious when using the Dust & Scratches filter. If you go too far with it, you could end up losing detail along with the unwanted specks. Sometimes a little elbow grease and the Rubber Stamp tool will be necessary to finish the job. When used in tandem with the Unsharp Mask filter, Dust & Scratches can work wonders. (See Chapter 16, Adjusting Tonality and Color, and Chapter 20, Using Filters. )

For practice with the Dust & Scratches filter using the publicity photo that is partially shown in Figure 19.2, open dust_and_scratches.psd in the ch19 folder on the Photoshop CS Savvy CD .