The auto region Tool allows you to select areas based on similar shades of color. To use the auto region Tool, you simply point and click the color you want to select in the active layer.
Take the diagram below for example. Using the Magic Wand Tool, it simply takes one click in the white area to make a selection of that space. click in the
To move the selection, see Moving Region selections.
Tolerance determines the range of colors that will be selected at the moment you click the pointer.
Enter a value from 0 to 255 in the Tolerance box. A low number will let you select colors very similar to the pixel you click; a high number will let you select a broader range of colors.