Masking Unmasked - Giordan on Graphics

The Photoshop manual devotes a whole two paragraphs to the toolset we look at in this chapter. The reason they can look at it in such brevity while we consider it in length is that the Dodge, Burn, and Saturation tools are very easy to use. A few paragraphs is all that is needed to understand the basics of how the tools work. Understanding when, where, and why to use them is a different story (see Figure 15.1).

The Dodge and Burn tools are based on the darkroom practice of dodging and burning photographs to control the amount of light, and hence the tonality of specific areas of an image. Although the enlarger allowed global changes to the entire image, photographers sometimes needed to lighten or darken specific areas or objects.

The same requirement exists in Photoshop, where it is sometimes necessary to modify an image locally rather than globally. The global commands such as Curves, Levels, or any other Adjust commands don't give the local control necessary in many instances. And although you can select an area and use something such as Curves, many find it to be a counter-intuitive approach.

The Dodge tool lightens an area as it is applied to a color image. In the darkroom, photographers would cut out a disk of cardboard and attach it to a stick or piece of stiff wire. When the enlarger was exposing the image, they would wave the tool over the area they wanted to lighten, restricting the light to the desired area. The reduced exposure resulted in a lighter image. The Dodge tool doesn't work in all modes

The Dodge tool does not work on Index color and Bitmap files. To use the tool on these file types, first convert them to RGB by selecting the Image menu and choosing Mode and RGB. After you finish with the tool, you can convert back to Index or Bitmap by selecting it in the Mode submenu. The Dodge tool offers a pair of tool controls in the Options dialog box, which is accessed by double-clicking the Dodge tool in the Toolbox. The Exposure control determines how quickly the area is affected. A higher setting lightens the area quickly, whereas a lower setting builds it up gradually. It is usually a better idea to start with a lower setting, which gives more control over the final result, as shown in Figure 15.2.