For touch-up purposes, you'll probably only need to use three of the Photoshop Elements tools: the Paintbrush (renamed the Brush tool in Elements 2.0), Pencil, and Eraser. If you're using some other photo editing software, you likely have access to tools that work the same as these three, although the tool names may be different.

• Paintbrush (Brush tool, in Version 2.0): This tool enables you to create a variety of paint strokes, depending on the options you select. You can paint using a soft, fuzzy brush to create strokes that are blurry at the edges. With a hard-edged brush, your strokes have precise edges. Regardless of brush style, the Paintbrush always applies the foreground color.

• Pencil: Like the Paintbrush, the Pencil applies the foreground color. But the Pencil can paint only hard-edged strokes. As a result, it's less useful in photo retouching because few subjects in a photo have perfectly hard edges. You might use the Pencil for doing things like fixing a break in a border, however, or to touch up sign lettering.

• Eraser: When you're working on any layer but the background layer, the Eraser becomes a digital paint remover. It rubs away existing pixels, enabling you to wipe away any paint that spills on an area you didn't intend to alter. By adjusting the tool's opacity, you can set the Eraser to completely eradicate pixels or just make them more translucent, so that pixels on the underlying layer become partially visible.

On the background layer, the Eraser applies the background color — but this approach is risky and should usually be avoided. If you want to paint with the background color, press X or click the Swap Colors icon in the tool box to make the current background color the foreground color. Then paint with the Paintbrush or Pencil.