All photography was originally monochrome, or black-and-white. Even after color film was readily available, black-and-white photography continued to dominate for decades, due to its lower cost and its “classic” photographic look. The tones and contrast between light and dark shadows define black and white photography.It is important to note that some monochromatic pictures are not always pure blacks and whites, but also contain other hues depending on the process. The cyanotype process produces an image composed of blue tones. The albumen process, first used more than 150 years ago, produces brown tones.
Many photographers continue to produce some monochrome images, often because of the established archival permanence of well processed silver halide based materials. Some full color digital images are processed using a variety of techniques to create black and whites, and some manufacturers produce digital cameras that exclusively shoot monochrome.