Photographic lighting

[2] Lighting is especially important for monochrome photography, where there is limited to no color information, and exclusively includes the interplay of highlights and shadows.

In the picture above, the photographer added a warming gel on the flash of the woman standing in a field in late afternoon light.

However, if masked out and put on a plain white or neutral gray background, the image of the woman would seem abnormally yellow.

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.

[6] 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.

The sun hitting the front of objects facing the camera acts as a "key light," creating highlights and casting shadows.

[3] Detail in shadows can be seen due to the reflection of sunlight off water vapor and dust in the atmosphere creating omni-directional "fill".

In natural lighting, the tone of the background is influenced by its reflective qualities and whether it is illuminated by the sun directly or skylight indirectly.

Another way is to supplement a fill source from the direction of the camera with reflectors placed near the sides of the foreground subject.

The Inverse-Square Law describes the predictable way a point light source radiates and changes in intensity with distance.

Even something as basic as a head and shoulders portrait must take inverse-square fall-off into account by posing the front of the subject's face as close or closer to the "key" light than the shoulder or any other body part if the goal is to make the front of the face the most strongly contrasting focal point on a darker background.

Lighting a scene with a tonal range or color cast which is out of context with what would typically be expected will cause the viewer to notice the environment and make other than normal assumptions about it.

It is also possible to create the impression of environmental context where none is seen in the photograph, such as the look of a person standing under a streetlight at night by using a grid flash attached to the ceiling of the studio with no fill source.

This method uses three separate lighting positions to give the photographer a great deal of control in illuminating the subject.