Photoshop has two categories of color -- a foreground color and a background color. You apply the foreground color when you use the type tools, the painting tools, or the shape tools. It is also the beginning color of the default gradient applied by the Gradient tool.

The background color is the color you apply with the Eraser tool (assuming you don't have layers) and is the ending color of the default gradient. When you increase the size of your canvas, you fill the additional canvas with the background color (also assuming you don't have layers). You find the swatches that represent the two color categories in the lower part of the Tools palette (also known as the Toolbox).

Here are a few tips about using tools with foreground and background colors:

• Use the Brush tool or the Pencil tool with the foreground color.
• Blend the foreground and background with the Gradient tool.
• Fill selected areas with the foreground color.
• Apply the background color by erasing.
• Use the Shape tools to create shapes that are filled with the foreground color.
• Add more background to your canvas and fill it with the background color.