During yesterday's short video of Mary Randlett, she used the term "burning in" when referring to developing her photos. Here is some info from Wikipedia about what this means.

Dodging and burning

From Wikipedia, the free encyclopedia

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 reduces the exposure for areas of the print that the photographer wishes to be lighter, while burning gives extra exposure to areas of the print that he or she wishes to 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, etc., 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.

Many modern digital imaging programs such as Adobe Photoshop have "dodge" and "burn" tools that mimic the effect on digital images.

By using completely opaque material as a cover over the preferred area for dodging or burning, absolutely no light will pass through and as a result, an outline of the material may be visible on the print. One way to prevent obvious cover-up lines is to slightly shake the burning material over the covered area while it is being exposed. Another way to prevent obvious cover-up lines is to use slightly less opaque material closer to the outline to produce a more subtle, faded effect.

Burning

To burn-in a print, the print is first given normal exposure. Next, extra exposure is given to the area or areas that need to be darkened. A card or other opaque object is held between the enlarger lens and the photographic paper in such a way as to allow light to fall only on the portion of the scene to be darkened.

Dodging

A card or other opaque object is held between the enlarger lens and the photographic paper in such a way as to block light from the portion of the scene to be lightened. Since the technique is used with a negative-to-positive process, reducing the amount of light results in a lighter image.