Dodging and burning are terms used in photography for a technique used during the printing process to manipulate the exposure of a selected area(s) on a photographic print, deviating from the rest of the image's exposure. Dodging decreases the exposure for areas of the print that the photographer wishes to be lighter, while burning increases the exposure to areas of the print that should be darker.

Any material with varying degrees of opacity may be used, as preferred, to cover and/or obscure the desired area for burning or dodging. One may use a transparency with text, designs, patterns, a stencil, or a completely opaque material shaped according to the desired area of burning/dodging.

Ansel Adams elevated dodging and burning to an art form. Many of his famous prints were manipulated in the darkroom with these two techniques. Adams wrote a comprehensive book on this very topic called The Print.

ADVANCED DODGING AND BURNING:

http://www.photovisionmagazine.com/articles/fstopprinting.htm