The paint bucket tool is another very useful tool. To use the paint bucket tool, simply click on the pouring paint bucket icon in the toolbox.
When you do so, you will see that your pointer changes into a paint bucket and that when you click on the canvas, you can fill areas with the color specified in the foreground color box
The paint bucket tool has all of te usual brush options as well as the opacity slider that we have already discussed for other drawing tools. It also allows you to modify the contents and tolerance values in the Options Palette.
Essentially, tolerance affects how broadly the paint bucket will fill. If set to a high tolerance, the tool will fill all shades of a color whereas if it is set low it will fill less shades. The figure below shows how a higher tolerance means that more shades of red will be filled with the blue color. We are going to discuss the content and tolerance options tomorrow along with other advanced features of the paint bucket. So for now, just practice filling basic blocks of your canvas.