Two of the most useful tools in Paint Shop Pro are the Dodge and Burn brushes. With these brushes, you can very gradually lighten or darken problem areas in a digital photograph without affecting the rest of the photo. These tools can also be used to add emphasis to particular areas in a photo while taking unwanted emphasis away from others.
The Dodge and Burn brushes can be found about mid-way down the tool panel on the left side of the Paint Shop Pro user interface as shown in the screenshot below. (Click any image for a larger view.)

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Although it may not be quite so apparent from the names of the tools, the Dodge brush is used to lighten areas while the Burn brush is used to darken them. One nice feature in Paint Shop Pro is that once you select one of these tools, you immediately have access to both of them, assuming that you have a two-button mouse. That is, if you select the Dodge brush, left-clicking the mouse will apply the dodge effect to your image while right-clicking will apply the burn effect. Likewise, if you select the Burn brush, left-clicking will apply the burn effect and right-clicking will apply the dodge effect.