When importing photos into Lightroom CC, the first thing you’ll want to do is begin processing the images. On the right side, under the Edit panel, the first set of edit controls available reside in the Light panel – aptly named, for it allows you to control the light levels of the photograph. From here it’s possible to adjust overall Exposure (brightness) of your image, alter Contrast, control Highlights, lift or reduce Shadows, and adjust the Whites and Blacks sliders.
If you have an underexposed image, it’s possible to increase the exposure and save an image that otherwise would be lost. However, the controls should be used sparingly, for if you’ve underexposed an image, even if you can retrieve that data through, say, increasing the exposure by a stop or…