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B&W Brightness & Brilliance
By Brian Ratty
© 1999
BRIGHTNESS RANGE
Brightness range refers to the range of contrasts in the light reflecting from the subject to be photographed. The brightness range of a subject stretches from its deepest shadows to its most brilliant highlights.
Two things affect the brightness range of a subject: the contrasts due to the effects of the light and the range of contrasts in the subject itself.
The highest brightness range possible occurs in the combination of extremely black shadows and extremely bright sunlight. The lowest brightness range is in the scene of exactly the opposite tone: one in which the contrasts are few and the tone values are in approximately the same place. For example, a scene with highest brightness range might be one in which there is a white house in hot sunlight with one side of the house in dark shadow. If the same house were seen on a foggy overcast day, there would be a very low brightness range.
If we think of a girl dressed in a white and black dress, we have an example of a high contrast range in the subject itself.
The brightness range of a subject affects the exposure and development of the negative. A scene with extremely high brightness range is difficult to record. Film latitudes, however, have been developed to such a degree of perfection that they can record much greater brightness ranges than was ever possible in the past. Nevertheless, there are extremes in light contrasts, which are too great for modern emulsions.
As the brightness range of the subject increases, the gamma, or degree of development required produce any given range of densities, decreases. In a subject of low brightness range a high gamma is necessary in development.
Therefore some photographers overexpose and underdevelop their negatives in recording scenes of extremely high brightness range. In scenes of low brightness range they use the opposite device: underexposing and overdeveloping the negative. This method of exposure and development is the foundation of the Zone System used by Ansel Adams.
Low Brightness Range
BRILLIANCE
Brilliance in negatives and prints should not be confused with mere contrast, for it refers to the quality as well as the variation with which the brightness values of the subject are recorded.
A print is said to have brilliance when it has a small area that is quite white, a small area that is quite black, and a good range of varying gray tones in between.
O = White white's
O = Black black'sPrints of the greatest brilliance are produced from negatives, which have been correctly exposed and developed so that they will print perfectly on normal paper.
Certain artificial aids to brilliance, such as abnormal development of the negative or use of contrast paper or filters, are rarely satisfactory and seldom produce the proper illusion. These aids should be reserved for subjects who are extremely dull and low in brightness range.
One of the greatest deterrents to brilliance in prints is negative fog. In the printing process brilliance will be increased by the correct exposure and development of the paper. Extended development tends to increase the brilliance of the print, up to a certain point. Overexposure and underdevelopment of the paper will give exactly the opposite effect.
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