Color Reversal Film
Color reversal film is film designed to produce a positive image when it's exposed in the camera. It's also referred to as slide film or transparency film. In order to view the film, light must be transmitted through it. It has to be lit from behind or the light can be projected through the film's image onto a viewing screen. This type of film comes in various ISO speeds and is excellent for making aerial slides. High-speed color reversal film is ideal for photography when the light level is low, such as the late afternoon or at dusk.
When you have to take color photos in through heavy haze or from high altitudes, the contrast can be improved slightly by having internegatives made from color slides. Reversal films are easily recognized by the suffix chrome in their names, such as Kodachrome and Fujichrome. Developed color reversal film can be used as a transparency slide for direct viewing or printed straight to color reversal paper. It can also be copied on a black-and-white film for making black-and-white prints, or copied to a color internegative for making color prints. Color reversal film costs a few dollars a roll.