Absolute Beginner's Guide to Digital Photography

Noise Filters: Despeckle and Dust & Scratches

The two most important Noise filters are Despeckle and Dust & Scratches. Despeckle

blends dots of color; Dust & Scratches is an amazing tool that blurs dust that might

have come through on a negative scan, but retains the sharpness of the actual

image.

Using Despeckle

If you scan a print at a high resolution, the actual paper grain will appear (see

Figure 13.11). One way around this is to scan the negative, but if you don’t have it

or can’t find it, you might have to remove this grain. The Despeckle Noise filter can

help.

200 ABSOLUTE BEGINNER’S GUIDE TODIGITAL PHOTOGRAPHY

FIGURE 13.11

An old depart-

ment store

photo scanned

at 600 samples

per inch. The

somewhat

70s-ish “tex-

tured” photo

pattern is

prominent.

The first thing to try is a filter called Despeckle. The Despeckle filter detects the edges

in an image (parts of the image with significant color changes such as the edge of a

roof against a sky) and blurs everything but the edges. By blurring, Despeckle

removes noise, yet is capable of preserving detail.

Too much Despeckle can blur the image. The goal is to remove film grain and retain

detail. The following steps walk you through the process:

1. After scanning an image, save the file with a new name.


2. Choose Filter, Noise, Despeckle. This filter has no dialog box, so the effects are
   immediate.