Dodging and burning are terms used in photography for a technique used during the printing process to manipulate the exposure of select areas on a photographic print, deviating from the rest of the image's exposure. In a darkroom print from a film negative, 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.[1]
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.
Many modern digital image editing programs have "dodge" and "burn" tools that mimic the effect on digital images.