Digital images created by scanning small older photographs often suffer from conspicuous dust and scratches. Photoshop has a filter to correct this problem but as usual the filter should be used with moderation for it also causes the photograph to lose some fine detail. The dust in the following picture (taken in Borneo) is very conspicuous against the smoothly graduated colours of the sunset. 

Choose Filter>Noise>Dust and Scratches (Filtre>Bruit>Antipoussières) and then play with the settings to achieve the best reduction of dust without affecting my student's lovely profile. Switch the preview on and off to see what effect your settings are having on the image.

Start with a low value for the radius and a high value for the threshold. and then gradually increase the radius and decrease the threshold until the dust defects are largely gone but without losing too much detail in the image.

The radius determines how far the filter searches for differences among pixels, so use the smallest radius value that still has a good effect on reducing the dust defects. (Increasing the radius makes the image blurry.)

The threshold determines how different the pixels’ values should be before they are eliminated. Start from a high value and then decrease gradually, stopping at the largest value that eliminates most of the defects.

Don't worry if some defects remain after your restrained use of the Dust and Scratches filter - there is another way of tackling the worst defects: the rubber stamp tool . This is actually a very interesting tool, useful in many contexts in addition to this one. the rubber stamp tool copies parts of the image into neighboring parts using a brush.

First, select the rubber stamp tool by clicking it. Then display the brush palette (called formes in French)  by pulling down the palette from the options bar in Photoshop 6 or using Window>Show Brushes if you are using Photoshop 5. Choose a medium-sized soft-edged brush from the middle row. Locate a defect somewhere in the picture and, hold down the Alt key and click about 1cm left of the defect. Then release the Alt key and click or 'paint' across the defect. As you do so, you will be copying a part of the image 1 cm left of where you 'paint' since this is the relative position that you pre-defined by Alt-clicking. Of course, you do not have to copy from 1cm to the left. You can copy from above or below or anywhere - it all depends on the relative positions of the Alt-Click and the subsequent click or drag. This tool is a little tricky to master, but it's well worth persisting. When you've done your best at removing the defects from the above image, save it and continue below.

Now that you have had some practice with the rubber stamp tool, try using it to turn this photo from Bali, Indonesia...

into this...

First, of course, you'll have to find the two differences between the two images... I cheated a bit and made use of the sharpening tool as well as the rubber stamp tool. This might also be a good time to try the smudge tool, but I think you'll find the rubber stamp tool more satisfying to use. See the toolbox page for help with the sharpening tool and the smudge tool.

As usual save your work when you're done.