Redirecting light from a camera’s flash away from the subject and onto a light-colored surface to diffuse and soften the effects of the flash.
Light from a flash can be directed toward and bounced off of a wall, ceiling, or specially-made bounce card or umbrella.
Nearly all cameras have some sort of flash built in or have a mount, called a hotshoe, that allows the user to mount an external flash. When a flash is used, the light hits the subject from the same perspective as the camera itself. This results in a relatively “flat” looking image...the entire subject is generally illuminated evenly with minimal shading.
By re-directing the light from the flash away from the subject and onto a semi-reflective surface, such as a wall or ceiling or diffuser mounted on the flash, the light approaches the subject from a perspective that is different from the camera. This results in a subject that is lit with more subtle lighting and produces different shading effects. Light intensity and shadows can be influenced by adjusting the direction of the flash, distance to the bouncing surface to the subject and/or camera, or using different colors of bounce surfaces.