Artificial light can be broadly defined as any light source that is not naturally occurring, such as light bulbs and flash strobes. Artificial light may be an uncontrolled part of the scene or location being photographed, such as street lights, or it may be purposely added and controlled for technical and creative purposes, such as a flash unit. The color temperature of artificial light can vary greatly depending on the source, from very cool from a fluorescent bulb, to very warm from an incandescent one.
Artificial light, such as flash, should be used judiciously when it comes to wildlife, to avoid stressing the animal or causing it harm. Flash is very useful in macro and close-up photography, where smaller apertures and lens extension require more light than may be available naturally. One of the most important factors in the effective use of artificial light is to ensure that it is soft, natural-looking, and of the proper color temperature in relation to the ambient light. This can be done with light modifiers, such as diffusers and gel filters.