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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?

Luminosity Control In Photoshop

When I study the scene in front of me for luminosity using this filter, if I like what I see through it, all I have to do in Photoshop is draw the saturation slider in Adobe Camera Raw to -100 (which desaturates the image and shows only the luminosity; in Photoshop CS3 and Lightroom, I simply press the Grayscale button). Doing this, I’ll usually achieve a decent black-and-white (luminosity) image right off the bat.

After getting a good luminosity image (by further refinement in Camera Raw or Lightroom, if necessary), I either keep it that way for a black-and-white print or convert it back to color. With this simple tool and correction, we see that luminosity is the key to controlling many important things in the image: color, shadow detail, highlight detail, midtone separation and tonal blending.

Luminosity Control In PhotoshopIn the examples, you can see the original color scene, the image with the 90 viewing filter and the final photograph converted to black-and-white. The viewing filter subtracts most of the color from the image and we view it in monotone, helping us to see the possibilities of the luminosity.

Seeing And Controlling Luminosity In Photoshop

While it’s relatively easy to see the reflected light from the surfaces of objects and control them with local burning and dodging in Lightroom and Photoshop, ambient light is quite another matter. As hinted by the quotes from Adams and Land, both are important for the "presence" of a good photograph and print, in color and black-and-white.

The struggle to find a method to reveal ambient light started for me more than 10 years ago. Through the work of Adams and realistic painters, I discovered that there exists in each photograph a web of light that represents the ambient "glue" that holds the feeling of the image together and allows it to unify. In reality, it’s a web of light that creates wholeness to the image.

Luminosity Control In PhotoshopPhotoshop has an effective tool to identify and modify this "web of light" in a photograph: Color Range under the Select Menu. To find this web in an image, I open Color Range and look at the Highlights, Midtones and Shadows as separate areas. The one that has a web of light that covers most of the image (it could be in one or all three areas) is then chosen using the Color Range command, which turns that area into a selection that can be manipulated with Curves or Levels or other tools.

A photograph usually contains both ambient and reflected light, but one will usually dominate the other. Think of reflected light as defining an object and ambient light as a feeling. Absolutely defining such aesthetic truths is impossible. By engaging ourselves in this discovery process, we see that luminosity has meaning. There’s a visual vocabulary of tonal value caused by luminosity in black-and-white and color images that’s created by the action of light alone, independent of content. The answers to any questions about luminosity must be treated as a continually unsolved riddle that always changes and offers us endless possibilities for an authentic response of expression in a photograph.

To see more of George DeWolfe's work, visit www.georgedewolfe.com.


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