Panchromatic emulsion is a type of

black-and-white Black-and-white (B&W or B/W) images combine black and white in a continuous spectrum, producing a range of shades of grey. Media The history of various visual media began with black and white, and as technology improved, altered to color. ...

photographic emulsion Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glas ...

that is sensitive to all

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, t ...

s of

visible light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

Description

A panchromatic emulsion renders a realistic reproduction of a scene as it appears to the human eye, although with no colors. Almost all modern photographic film is panchromatic. Some older types of film were orthochromatic and were not sensitive to certain wavelengths of light. As naturally prepared, a silver halide

is much more sensitive to blue and UV light than to green and red wavelengths. The German chemist Hermann W. Vogel found out how to extend the sensitivity into the green, and later the orange, by adding sensitising dyes to the emulsion. By the addition of

erythrosine Erythrosine, also known as Red No. 3, is an organoiodine compound, specifically a derivative of fluorone. It is a pink dye which is primarily used for food coloring. It is the disodium salt of 2,4,5,7-tetraiodofluorescein. Its maximum absorba ...

the emulsion could be made orthochromatic while some

cyanine Cyanines, also referred to as tetramethylindo(di)-carbocyanines are a synthetic dye family belonging to the polymethine group. Although the name derives etymologically from terms for shades of blue, the cyanine family covers the electromagnetic ...

derivatives confer sensitivity to the whole visible spectrum making it panchromatic. However, his technique was not extended to achieve a fully panchromatic film until the early 1900s, shortly after his death. Panchromatic stock for still photographic plates became available commercially in 1906. The switch from orthochromatic film, however, was only gradual. Panchromatic plates cost two to three times as much, and had to be developed in total darkness, unlike orthochromatic—which, being insensitive to red, could be developed under a red light in the darkroom. And the process that increased the film's sensitivity to yellow and red also made it oversensitive to blue and violet, requiring a yellow-red lens filter to correct it, which in turn reduced the total amount of light and increased the necessary exposure time. Orthochromatic film proved troublesome for motion pictures, rendering blue skies as perpetually overcast, blond hair as washed-out, blue eyes nearly white, and red lips nearly black. To some degree this could be corrected by makeup, lens filters, and lighting, but never completely satisfactorily. But even those solutions were unusable for

additive color Additive color or additive mixing is a property of a color model that predicts the appearance of colors made by coincident component lights, i.e. the perceived color can be predicted by summing the numeric representations of the component colo ...

motion picture systems like

Kinemacolor Kinemacolor was the first successful colour motion picture process, used commercially from 1908 to 1914. It was invented by George Albert Smith in 1906. He was influenced by the work of William Norman Lascelles Davidson and, more directly, E ...

and Prizma color, which photographed on black-and-white stock behind alternating color filters. In those cases, negative film stock after it arrived from the manufacturer had to be passed through a color-sensitizing solution, a time-consuming process that increased the film's cost from 3 cents per foot to 7 cents. Eastman Kodak, the supplier of motion picture film, introduced a panchromatic film stock in September 1913, available on special order for photographing color motion pictures in additive systems. Photographers began using it for black-and-white films too in 1918, primarily for outdoor scenes. The company introduced Kodak Panchromatic Cine Film as a regular stock in 1922. The first black-and-white

feature film A feature film or feature-length film is a narrative film (motion picture or "movie") with a running time long enough to be considered the principal or sole presentation in a commercial entertainment program. The term ''feature film'' originall ...

photographed entirely on panchromatic stock was '' The Headless Horseman'' (1922). But early panchromatic stock was more expensive, had a relatively short shelf-life, and was more difficult for laboratories to process because it required working in total darkness. Not until the prices were equalized by competition in 1926 did it become used more widely than orthochromatic stock. Kodak discontinued manufacturing general-purpose orthochromatic motion picture film in 1930.Kodak: Chronology of Motion Picture Films, 1889 to 1939
Digital panchromatic imagery of the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

's surface is also produced by some modern satellites, such as QuickBird,

Cartosat The Cartosat is a series of Indian optical earth observation satellites built and operated by the Indian Space Research Organisation (ISRO). The Cartosat series is a part of the Indian Remote Sensing Program. They are used for Earth's resource ...

and IKONOS. This imagery is extremely useful, as it is generally of a much higher (spatial) resolution than the

multispectral Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, ...

imagery from the same satellite. For example, the QuickBird satellite produces panchromatic imagery having a pixel equivalent to an area , while the

pixels represent an area of .

References

{{reflist Photographic film types

Description

See also

References