In photographic terms, noise means graininess—colored speckles. Noise is a common problem in digital photography, especially in low-light shots taken with older cameras. Some cameras, for example, claim to have “anti-blur” features that turn out to be nothing more than goosed-up ISO (light-sensitivity) settings in low light. But over ISO 800 or so, the resulting digital noise can be truly hideous.

If a photo looks noisy (grainy), you can lessen the effect by moving the Adjust panel’s De-noise slider to the right. To gauge how much, first zoom in on your image to 100 percent size (press the 1 key), then keep an eye on a dark area or the sky as you move the slider. Generally speaking, moving the slider more than halfway softens your image too much.