reversal processing

The reversal process in photography is a method used to create a positive image directly from a negative image, rather than producing a separate negative first. This is achieved by developing the exposed film partially, then bleaching the initial negative image. The remaining unexposed silver halide is then exposed to light and developed, resulting in a positive image.1

This technique is particularly notable in the creation of color slides, such as Kodachrome film, which uses reversal processing to produce color transparencies suitable for projection. In this process, each color-sensitive layer of the film is reversal-processed to create a positive dye image complementary to its spectral sensitivity. This method bypasses the need for a separate negative generation, saving costs and time.234