Here's an easy way to whiten teeth in Photoshop, no selections required:

Make a new layer, set the blend mode to Overlay or Soft Light, and fill with 50% gray. (this can be done all at once by holding down the alt key in Windows, I think it's the Opt key on a Mac, while adding a new layer from the layers palette).

Now, paint over the teeth, or any area you need to lighten, with the color set to white, and a low opacity. I prefer a soft-edged brush, but you can use any brush you like, and usually start with an opacity of around 10%.

This works on any area you need to lighten. If you want to darken an area, just paint with black instead of white.

That's a good tip, Patricia. Thanks for posting.

Ed

This is a good tip- especially if the photo is b/w. However, you get much better results by making a very rough selection of the teeth, then in the layer palette add a saturation layer - this will bring up a masked layer of your original, with only the teeth roughly selected- in the saturation window, take out the yellow, then on the master bring up the lightness, click ok. If you find that it is too bright you can now just lower the opacity of that layer. You can of course then use the paint brush on your mask to bring in or take out areas you don't want effected.

....selectively lightening dark areas of a photo, such as faces in shadow. You just have to make sure you set the opacity of the white brush to around 10% and use a very light hand. Allows great amount of control.

Great tip!!!

Thanks for sharing Patricia!!!

.... and a great variation of usage!!!

Thanks ajava!!!

That's your basic Dodge and Burn on a layer. Or as many have seen. PWL.
I actually like the burn tool and sponge tool for teeth and eyes..
Snook

I have an illustrated "Tip" on my site that demonstrates how to whiten teeth with the Brush tool.

http://www.thelightsrightstudio.com/tip-whitening-brightening-teeth.htm

Cheers,

Mitch