Photographic lighting refers to how a light source, artificial or natural, illuminates the scene or subject that is photographed; put simply, it is lighting in regards to photography. Photographers can manipulate the positioning and the quality of a light source to create visual effects, potentially changing aspects of the photograph such as clarity, tone and saturation to create an accurate rendition of the scene.

Lighting determines exposure and can be used to create effects such as low-key and high-key lighting, both of which involve the contrast between darker and lighter elements in a scene. Lighting is especially important for monochrome photography, where there is limited to no color information, and exclusively includes the interplay of highlights and shadows.

The main sources of light for photography are:

Lighting creates the 2D pattern of contrast that the brain interprets in order to recognize 3D objects in photographs. When viewing something in-person, the brain relies on stereoscopic vision, parallax, shifting focal in addition to the clues created by the highlight and shadow patterns the light on the object creates. When viewing a photo, however, the brain tries to match the patterns of contrast and color it sees to other sensory memories.

The baseline for what seems "normal" in lighting is often the direction and character of natural and artificial light as well as the context provided by other clues. In the picture above, the photographer added a warming gel on the flash of the woman standing in a field in late afternoon light. The viewer knows the time of day from the angle of the shadows; therefore, neutral color balance would have seemed odd in that context. However, if masked out and put on a plain white or neutral gray background, the image of the woman would seem abnormally yellow.

While the goal of photography is not necessarily to create an impression of normality, knowing what the audience normally expects to see is required to pull off a lighting strategy that fools the brain. Light direction relative to the camera can make a round ball appear to be a flat disk or a sphere. The position of highlights and direction and length of shadows will provide other clues to shape and can even indicate the time of day. The tone of the shadows on an object also can provide contextual clues about the time of day, the environment in which the photo was taken, and even the mood of the person.

A skilled photographer can manipulate how a viewer is likely to react to the content of a photo by manipulating the lighting. When shooting outdoors, changing locations may be required, as well as waiting for the ideal time of day (or even the ideal time of year in some cases) for the lighting to create the desired impression in the photo. Photographers may also manipulate natural lighting by using reflectors or flash. In a studio setting, however, there is no limit to the options a photographer has for lighting. Objects can be made to either look normal as "seen by the eye" or surreal as the goals for the photograph require. Usually, the viewer's reaction will depend on whether or not the lighting seems normal/natural compared to other clues.

Mixing natural and artificial light can be a difficult process. A mistake less-skilled photographers often make when mixing flash and natural lighting is not matching the light from the flash with the highlight and shadow clues seen in a background lit with ambient light. For example, if the background is illuminated by the setting sun, but the face in the foreground appears to have been photographed at noon, it will not seem normal, as the lighting clues do not match.