Tungsten film is
photographic film
Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the ...
designed to accurately represent colors as perceived by humans under
tungsten
Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...
light; the more usual color films are "daylight films", balanced to produce accurate colours under direct light from the sun or electronic flash. Tungsten film was developed for photographers who use tungsten lights, also known as
photofloods, which have a much lower
color temperature
Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most clos ...
than daylight, at 3200
kelvin
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By de ...
s or 3400 kelvins. It also renders colors more accurately than daylight film under ordinary household incandescent lighting.
On daylight-balanced film
tungsten lighting produces a spectrally accurate rendition of a scene; but human vision adjusts to the color of the lighting and perceives colors as if under daylight, seeing a spectrally accurate image as having a yellow-orange cast. Tungsten film is balanced in such a way that this lighting is recorded with a subjectively neutral color balance. When shot outdoors, tungsten film produces a strong blue cast, an effect which is often used purposely to create different color contrasts. In the motion picture industry the use of underexposed tungsten-balanced film in an outdoor setting is a common way of producing a "
day for night" effect, whereby film shot during the daytime looks as if it had been shot at night.
Tungsten slide films are designed to provide accurate exposure as well as color rendition even when exposed according to
exposure meter readings indicating a long exposure; tungsten film can be used to avoid
reciprocity failure which often occurs when using long exposures. Common
film speed
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system introduced in 1974. A closely related system, also known as IS ...
s for tungsten-balanced slide film are ISO 64, 160, and 320.
Examples
* Cinestill 800t
* Kodak 500t
* Ektachrome 64T
References
*Hedgecoe, John. ''The New Manual of Photography.'' 1st ed. New York: DK Inc, 2003. 128-130.
*https://cinestillfilm.com/collections/800tungs
*https://www.kodak.com/uploadedfiles/motion/TI2647.pdf
Photographic film types
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