Ortho­chromatic refers to a type of photographic film or paper that is sensitive to all colors of light except for red. This means it can accurately capture colors like blue and green, but red light does not affect the film's sensitivity. As a result, orthochromatic materials produce images with a different tonal range compared to panchromatic materials, which are sensitive to all colors. Historically, orthochromatic film was widely used in photography before the development of panchromatic film. It was particularly popular in the early 20th century for capturing black-and-white images, especially in landscape photography and portraiture. Today, orthochromatic materials are still used in some specialized applications, such as graphic arts and scientific imaging.