Pre-flashing
Encyclopedia
In cinematography
and photography
, pre-flashing is the exposure of the film
or other photosensor to uniform light
prior to exposing it to the scene to be imaged. This adds a bias to the overall light input recorded by the sensor.
It is sometimes used for artistic effects, as it can be used to add a colour cast to shadow
s without significantly affecting highlights.
It is also used in fields such as astronomy
to bias CCD
image sensors into a linear region, improving their low-light sensitivity.
Cinematography
Cinematography is the making of lighting and camera choices when recording photographic images for cinema. It is closely related to the art of still photography...
and photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
, pre-flashing is the exposure of the film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
or other photosensor to uniform light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
prior to exposing it to the scene to be imaged. This adds a bias to the overall light input recorded by the sensor.
It is sometimes used for artistic effects, as it can be used to add a colour cast to shadow
Shadow
A shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or reverse projection of the object blocking the...
s without significantly affecting highlights.
It is also used in fields such as astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
to bias CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
image sensors into a linear region, improving their low-light sensitivity.