Orthochromatic film is a type of photographic film that is sensitive to blue and green light, but not red. The word "orthochromatic" is spelled with the letter combination "ch" which represents the /k/ sound, not the /tʃ/ sound as in words like "chocolate." The IPA phonetic transcription for "orthochromatic" is /ˌɔːθəkrəˈmætɪk/, with the stressed syllable on the second syllable. Correct spelling of technical terms such as "orthochromatic" is important for clear communication within the field of photography.
Orthochromatic film refers to a type of photographic film that is sensitive to and captures only certain regions of the visible light spectrum. Unlike traditional black and white film, which is sensitive to all wavelengths of visible light, orthochromatic film is specifically designed to be insensitive to red light. This means that objects that appear red to the human eye will be rendered with minimal or no distinction on orthochromatic film.
The specialized construction of orthochromatic film involves using a silver halide emulsion that is primarily sensitive to blue and green light, resulting in a film that registers these colors more pronouncedly. This selective sensitivity allows photographers to achieve specific aesthetic effects, as it enhances the contrast between blue and green hues while downplaying the presence of red tones during the capturing process.
The development of orthochromatic film revolutionized photography, especially within certain genres such as portraits and landscapes. By reducing the sensitivity to red light, this film type offers photographers unparalleled creative control, enabling them to manipulate the resulting image's tonality and contrast.
Although orthochromatic film saw significant advancements in the early 20th century, it has become less popular in the digital age. However, among film enthusiasts and professionals, it still holds value for its unique tonal rendering and the ability to evoke a certain vintage or nostalgic look in photographs.
The term "orthochromatic" is derived from the combination of two Greek roots: "ortho" meaning "straight" or "correct", and "chroma" meaning "color". In the context of photography, "orthochromatic" refers to the sensitivity of a photographic film or plate to a range of colors, especially those in the blue and green spectrum. Orthochromatic films were the earliest type of panchromatic films that were sensitive to a broader range of colors, allowing for improved rendition of different tones and shades.