This Photoshop tutorial is designed to instruct on the use of Photoshop's Burn and Dodge Tool to adjust highlight and shadow tone in a defined area. Unlike Levels, Curves, and Brightness/Contrast, which globally adjust tonal value, the Burn and Dodge tools use Photoshop Brushes to selectively alter color, with their effectiveness, size, and intensity (described as "Opacity" and "Flow" in the paintbrush mode) being adjustable in the same way that the paintbrush is set.
The objective is to even-out the overall contrast of the image so that the bright (highlighted) areas of the photograph are balanced with the darker shadow areas. Keep in mind that there is a limit to how much you can brighten dark areas, and darken highlighted areas that are blown out. If there is no contrasting pixel information in the darkest or lightest areas, no amount of manipulation will add back the non-existing data. Use Photoshop's Histogram to see how much pixel data is concentrated at the furthest extremes.
Burning & Dodging to Adjust Highlight, Midtones, & Shadow
Burning a photograph with the "Burn Tool (O)" darkens an area, while dodging a photograph with the "Dodge Tool (O)" lightens the area. You can adjust the tonal range that each tool effects by altering the "Range" setting in the menu-bar's pull-down menu. Both the Burn Tool and Dodge Tool have three range settings: Highlights, Midtones, and Shadows. You can also adjust the intensity of the tool by adjusting its "Exposure" setting.
Exposure Setting
You can also adjust the intensity of the tool by adjusting its "Exposure" setting. The Exposure setting works in the exact same way as the Brush Tool (B) "Opacity" and "Flow" settings. Lower exposure settings are always preferable, used in conjunction with larger brush sizes. This helps in making subtle changes that are easily reversable.
The first color and tone adjustments to your photo should be made using Photoshop's Curves, and Color Balance tools to make any global adjustments to the photograph.
When using the Dodge Tool to lighten an area, start with the tool set to 'Midtones,' with a wide, soft-edged brush, and a low Exposure setting. If the color washes out, use the Sponge Tool to saturate the area.
Technical Note: If you try to lighten a dark shadow area with the Dodge Tool set to 'Shadows' you will wash-out the area, destroying the black levels. Conversly, if you try to darken a light area with the Burn Tool set to 'Highlights' you will muddy up the light areas, and loose your correct highlight white-point.
When using the Burn Tool to darken an area, the same rules apply, and again you should start with the tool set to 'Midtones,' using a wide, soft-edged brush, and low Exposure setting. In this case, if the color over-saturates, use the Sponge Tool to de-saturate the area.
The key to using Photoshop's Burn and Dodge Tools, as is the case with all of Photoshop's tools and filters, is to try not to do too much with any one tool. In any given photograph, there is only so much pixel information, an you can only push those pixels so far, before the results turn bad.
Technical Note: I have found that the "Highlight" setting can make alterations that are unnatural or extreme, and this setting can significantly alter hue and dramatically increase saturation. great care should be exercised when using the Highlight setting, and the "Exposure" setting should be set very low. If the saturation level is increased too dramatically you can use the burn tool's "Sponge Tool" setting to desaturate the area. Make sure to use the pulldown menu to set the brush to "Desaturate."
