Double exposure (photography)

See "Double Exposure" for other uses of this term

Apollo 8 launch. The photo is a double exposure, as the Moon was not visible at the time of launch (NASA).

In film and photography, double exposure is a technique in which a piece of film is exposed twice, to two different images. The resulting photographic image shows the second image superimposed over the first. The technique can be used to create ghostly images or to add people and objects to a scene that were not originally there. It is frequently used in photographic hoaxes.

It is considered easiest to have a manual winding camera for double exposures. On automatic winding cameras, as soon as a picture is taken the film is typically wound to the next frame. Some more advanced automatic winding cameras have the option for multiple exposures but it must be set before making each exposure. Manual winding cameras with a multiple exposure feature can be set to double-expose after making the first exposure.

The problem with double exposures, is that if too much film is exposed over the 2 shots, the picture will turn out overexposed. Medium to low light is ideal for double exposures. Also, it is important to use a tripod for double exposures. If the setting of the two shots do not line up almost exactly, you won't get the desired effect and the background will be blurry looking, as well as the target.

Double exposures are not the limit, as multiple exposures are possible, but the photographer should try not to overexpose the film.

Another way to superimpose pictures is digitally, using a software photo editor like Adobe Photoshop or GIMP. Simply alter the opacity of the two images and line them up over each other.