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 th ...
designed to accurately represent colors as perceived by humans under
tungsten
Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolat ...
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 than daylight, at 3200
kelvin
The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and phys ...
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
Day for night is a set of cinematic techniques used to simulate a night scene while filming in daylight. It is often employed when it is too difficult or expensive to actually shoot during nighttime. Because both film stocks and digital image s ...
" 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
In photography, reciprocity is the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states t ...
which often occurs when using long exposures. Common
film speeds 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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