Ronald Moravec , May 26, 2008; 01:55 a.m.
I think the one on the right is better. With photoshop elements or photoshop, use levels, just the blue channel. If you have curves, select the blue one and adjust the center point to upper left or lower right.
Typically photos have areas that get too light or too dark. In the darkroom, we burn and dodge these small areas. Photoshop has burn and dodge tools. Sometimes even better is to make a new layer, layer- new- change blending mode to overlay-check the box that says fill with 50% grey. Now paint on that layer with white to lighten- black to darken.
See The Lights Right Studio, digital darkroom tab, go to video tutorials, for a nice lesson.