1. Open the document and make a duplicate layer.

2. Turn off the original layer.

3. Zoom in on the area we will be working on, the mouth of the man.

4. Click the quick mask button on the tool bar. It is the button just under the foreground and background colors on the swatch palette. It is the button on the right.

5. Select the brush tool and use the bracket keys to change the size of the brush as you are working. Be sure the foreground and background colors are black and white. Use black to create the mask. Use white to erase the mask.

6. Begin painting on the teeth, you will see the red mask being applied to the teeth. We know that a mask will mask out the selected area of an image. Click the first quick mask button to go out of quick mask. You will see the selection you have made.

select / inverse. to select just the teeth.

7. You will have many choices here to change the color of the teeth. Try "image/ adjust/ hue and saturation. The teeth have a yellow cast to them so here you want to choose yellows instead of "master". Drag the saturation slider to the left to eliminate the yellow cast to the teeth. Turn off the top layer and turn on the original layer to see your results.

You may need to use the "reds" as well as the "yellows" in the hue and saturation dialog box for the bad teeth image as they are very discolored. Also try the dodge tool to lightly whiten the teeth.

8. The quick mask mode can be used to make selections of complicated areas of an image. Always remember to use select / inverse to choose the area to effect.