Photoshop has a neat filter that will eliminate most dust and scratches. The Dust and Scratches filter looks for spots that differ from their surroundings in color or brightness then blurs the surrounding color into the spots to eliminate them.
- In Photoshop open your image and create a duplicate layer.
- Working on the duplicate layer, choose Filter > Noise > Dust & Scratches. A Dust & Scratches pop-up window will appear.
- Use the radius slider to control how much you blur.
- Then use the Threshold slider to restore the grain. The Threshold slider fine tunes the blurring to only the very different spots.
To prevent a photo that is just too blurry there may be some large spots left after applying the filter. These can be corrected using other methods. And there may be spots blurred that you actually want like highlights on jewelry. These can be restored by erasing the blurred area so the original layer below shows through or by cut & pasting the area from the original layer.
The filter is fun to play with. Additional layers can be added of the trouble areas and filtered even more. Sorry this web browser doesn't let me put images that are detailed enough to really show off the dust removal but hopefully you get the idea from these...
Now you see it Now you don't