Adjust lighting

On the Lightroom on the web homepage, select All Photos.

Select an image to open it in detail view, and then select Edit .

Select Light.

Within the Light dropdown, adjust the given sliders: 

Exposure: Controls the overall brightness of your image. Move the slider left to darken the image or right to brighten it.
Contrast: Adjusts the difference between light and dark areas. Move the slider left to reduce contrast and right to enhance it.
Highlights: Controls the brightness of the lighter areas in your image. Move the slider left to darken highlights and recover details, or right to brighten highlights and reduce detail.
Shadows: Adjusts the brightness of the darker areas in your image. Move the slider left to deepen shadows or right to lighten them and reveal details.
Whites: Sets the white point of the image. Move the slider right to make more colors appear completely white.
Blacks: Sets the black point of the image. Move the slider left to make more colors appear completely black.

Select Share .