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Wednesday, August 1, 2007

Luminosity Control In Photoshop

What does it take to visualize luminosity in black-and-white and color photography, then see and control it in Photoshop?

Dr. Edwin Land, from the 1978 Polaroid annual report:

"...the photograph is two entirely different kinds of report transmitted to us by what appear to be mixed languages, the language for delineating objects and the language for displaying illumination.

"There haven’t been many great photographers in history, but the great ones usually turn out to be masters of the vocabulary of these two utterly different languages in black and white photography. For most would-be photographers these languages are mixed together and never disentangle, like the babble of voices at a cocktail party. The breathtaking competence of the great photographer is to cause the object of his choice to be revealed with symphonic grandeur, meticulous in detail, majestic in illumination."

Ansel Adams, from Natural Light Photography (1952): "Light, to the accomplished photographer, is as much an actuality as is substance such as rock and flesh; it is an element to be evaluated and interpreted. The impression of light and the impression of substance which are achieved through the careful use of light are equally essential to the realistic photographic image...To utilize it (natural outdoor light) fully you must know how to evaluate its intensities and qualities, not only in their effect on sensitive emulsions, but also in relation to the intangible elements of insight and emotion that are expressed in a good photograph. A certain esthetic philosophy is involved; something more than the physical conditions of light and exposure...the chief problem is to preserve the illusion of light falling upon the subject. A print intended to convey an emotional impression might differ from a normal photographic record."

Both Land and Adams are talking here about the same thing. They’re talking in general terms about the two types of light that a photographer has to deal with: the light reflecting from a subject (reflected light) that causes its texture and form and the light falling on the subject (ambient light) that causes the overall "mood" or aesthetic character of the image. The quality of light both reflected from the object and the ambient illumination falling on the entire scene are represented in the photographic print by luminosity alone.

Visualizing Luminosity
Kodak Wratten 90 monochromatic viewing filterTaking time to visualize and control the luminosity in a photograph will pay rich rewards in the print. The first tool that I use for this purpose is an item borrowed from traditional photography that helped photographers visualize a scene in black-and-white before taking the picture: a Kodak Wratten 90 monochromatic viewing filter.

Tiffen #1 B&W Viewing filterThe Tiffen #1 B&W Viewing filter is essentially the same filter, just in a fancier (and handier) viewer. The filter itself is amber, but it cancels out color and turns the world into a monochromatic view that shows the contrast relationships and tonal mergers that will occur in black-and-white photo-graphs. This filter also is used extensively in the motion-picture industry for the same purpose.

The 90 helps us to see a world that we have trouble visualizing. It’s available in many forms, from the original Kodak gel to the specially made viewers by Tiffen.


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