Light leak

This light is diffused, although parts within the camera may cast shadows or reflect it in a particular way.

Within the lomography movement it is seen as a positive effect, giving photos character.

One frequent source of light leaks in 35 mm cameras is around the film door due to degrading foam.

It is possible to have a "virtual" light leak in spectral regions, like portions of the IR spectrum at room temperature, where surfaces inside the system emit significant amounts of radiation.

[2] Or they can be created entirely digitally, with common photo-editing software packages such as Adobe Photoshop, and overlaid into the image.