• Clone (or rubber stamp): The Clone tool does exactly what it implies: It replicates good areas of an image, so you can hide damaged areas. The source (the “good” area) can be from the same photo or an entirely different one.
• Airbrush: The Airbrush tool simulates an actual airbrush or spray-paint can when applying a color. The longer you hold the airbrush over the image, the greater the effect. Airbrush options include the size and shape of the brush, as well as the spray’s intensity.
• Dodge: This lightens too-dark areas and brings out detail. Dodge takes its name from the traditional darkroom technique of holding back some of the light when printing a photo.
• Burn: The Burn tool is the opposite of Dodge: It darkens areas of the image that are too light.
Opacity measures a tool’s intensity: in other words, how strong an effect you get each time you apply the tool. High opacity means you’ll produce the tool’s full effect with one or only a few clicks (or strokes). Low capacity means each application will yield a more subtle result.