Photographic film

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This article is mainly concerned with still photography film. For motion picture film, please see film stock.

Film was the only form of photography until the early 21st century, when digital photography drew consumers to digital. Although modern photography is predominantly digital, more and more photographers are rediscovering film or discovering film for the first time.[1] Film continues to be used by an ever increasing number of enthusiasts and professionals,[2] and remains the standard to film photographers because of its distinctive film look. Film has seen a renewed interest by a new generation of photographers,[3] and there has been a steady increase in sales following the major drop in sales in 2011.[4] 2012 seems to mark the beginning of the rise of popularity of film again.[5][6] Kodak Alaris and Lomography teamed up in 2013 to increase manufacturing and sales of photographic film.[7] FILM Ferrania along with crowd funding via Kickstarter, met and exceeded their goal to finance the relocation of key machinery needed to resume production of film again, and production is expected to begin around the end of 2015.[8] The "Decline and Rise" and the current state of film in 2015 is summed up in these words "It seems to be evolving into something else that we didn’t know before."[9] Film is no longer the generic media of photography ever since digital came along. Film is and will be evolving to meet the tastes of those photographers that don't want "generic." This is where branding comes in to distinguish one film from another, and promote each film's uniqueness. It is therefore, fundamental that manufacture's and coater's have their brand on every roll they sell in the form of a logo stamp, right next to the re-branded marketing name used to target specific markets. "Branding is fundamental. Branding is basic. Branding is essential. Building brands builds incredible value for companies and corporations." [10]

Overview[edit]

Photographic film is a strip or sheet of transparent plastic film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine the sensitivity, contrast and resolution of the film.[11] The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to ultraviolet, X-rays and high-energy particles. Unmodified silver halide crystals are sensitive only to the blue part of the visible spectrum, producing unnatural-looking renditions of some colored subjects. This problem was overcome with the discovery that certain dyes, called sensitizing dyes, when adsorbed onto the silver halide crystals made them respond to other colors as well. First orthochromatic (sensitive to blue and green) and finally panchromatic (sensitive to all visible colors) films were developed. Panchromatic film renders all colors in shades of gray approximately matching their subjective brightness. By similar techniques special-purpose films can made sensitive into the infrared (IR) region of the spectrum.

In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, which blocks light and appears as the black part of the film negative. Color film has at least three sensitive layers, incorporating different combinations of sensitizing dyes. Typically the blue-sensitive layer is on top, followed by a yellow filter layer to stop any remaining blue light from affecting the layers below. Next come a green-and-blue sensitive layer, and a red-and-blue sensitive layer, which record the green and red images respectively. During development, the exposed silver salts are converted to metallic silver, just as with black-and-white film. But in a color film, the by-products of the development reaction simultaneously combine with chemicals known as color couplers that are included either in the film itself or in the developer solution to form colored dyes. Because the by-products are created in direct proportion to the amount of exposure and development, the dye clouds formed are also in proportion to the exposure and development. Following development, the silver is converted back to silver salts in the bleach step. It is removed from the film in the fix step. Fixing leaves behind only the formed color dyes, which combine to make up the colored visible image.

History[edit]

Advertisement for Ansco Speedex Film, 1922.

Early photography in the form of Daguerreotypes did not use film at all. The light-sensitive chemicals were formed on the surface of a silver-plated copper sheet. The alternative calotype process produced paper negatives. Beginning in the 1850s, thin glass plates coated with photographic emulsion became the standard medium. Although fragile and heavy, the glass used for photographic plates was of better optical quality than early transparent plastics and was, at first, less expensive. Plates continued to be used long after the introduction of film, and are still manufactured for scientific use.

Hurter and Driffield began pioneering work on the light sensitivity of photographic emulsions in 1876. Their work enabled the first quantitative measure of film speed to be devised.

The first flexible photographic roll film was marketed by George Eastman in 1885, but this original "film" was actually a coating on a paper base. As part of the processing, the image-bearing layer was stripped from the paper and transferred to a hardened gelatin support. The first transparent plastic roll film followed in 1889. It was made from highly flammable nitrocellulose ("celluloid"), now usually called "nitrate film".

Although cellulose acetate or "safety film" had been introduced by Kodak in 1908,[12] at first it found only a few special applications as an alternative to the hazardous nitrate film, which had the advantages of being considerably tougher, slightly more transparent, and cheaper. The changeover was not completed for X-ray films until 1933, and although safety film was always used for 16 mm and 8 mm home movies, nitrate film remained standard for theatrical 35 mm motion pictures until it was finally discontinued in 1951.

Spectral sensitivity[edit]

Early photographic plates and films were usefully sensitive only to blue, violet and ultraviolet light. As a result, the relative tonal values in a scene registered roughly as they would appear if viewed through a piece of deep blue glass. Blue skies with interesting cloud formations photographed as a white blank. Any detail visible in masses of green foliage was due mainly to the colorless surface gloss. Bright yellows and reds appeared nearly black. Most skin tones came out unnaturally dark, and uneven or freckled complexions were exaggerated. Photographers sometimes compensated by adding in skies from separate negatives that had been exposed and processed to optimize the visibility of the clouds, by manually retouching their negatives to adjust problematic tonal values, and by heavily powdering the faces of their portrait sitters.

In 1873, Hermann Wilhelm Vogel discovered that the spectral sensitivity could be extended to green and yellow light by adding very small quantities of certain dyes to the emulsion. The instability of early sensitizing dyes and their tendency to rapidly cause fogging initially confined their use to the laboratory, but in 1883 the first commercially dye-sensitized plates appeared on the market. These early products, described as isochromatic or orthochromatic depending on the manufacturer, made possible a more accurate rendering of colored subject matter into a black-and-white image. Because they were still disproportionately sensitive to blue, the use of a yellow filter and a consequently longer exposure time were required to take full advantage of their extended sensitivity.

In 1894, the Lumière Brothers introduced their Lumière Panchromatic plate, which was made sensitive, although very unequally, to all colors including red. New and improved sensitizing dyes were developed, and in 1902 the much more evenly color-sensitive Perchromo panchromatic plate was being sold by the German manufacturer Perutz. The commercial availability of highly panchromatic black-and-white emulsions also accelerated the progress of practical color photography, which requires good sensitivity to all the colors of the spectrum for the red, green and blue channels of color information to all be captured with reasonable exposure times.

However, all of these were glass-based plate products. Panchromatic emulsions on a film base were not commercially available until the 1910s and did not come into general use until much later. Many photographers who did their own darkroom work preferred to go without the seeming luxury of sensitivity to red—a rare color in nature and uncommon even in man-made objects—rather than be forced to abandon the traditional red darkroom safelight and process their exposed film in complete darkness. Kodak's popular Verichrome black-and-white snapshot film, introduced in 1931, remained a red-insensitive orthochromatic product until 1956, when it was replaced by Verichrome Pan. Amateur darkroom enthusiasts then had to handle the undeveloped film by the sense of touch alone.

Color[edit]

Experiments with color photography began almost as early as photography itself, but the three-color principle underlying all practical processes was not set forth until 1855, not demonstrated until 1861, and not generally accepted as "real" color photography until it had become an undeniable commercial reality in the early 20th century. Although color photographs of good quality were being made by the 1890s, they required special equipment, long exposures, complex printing or display procedures and highly specialized skills, so they were then exceedingly rare.

The first practical and commercially successful color "film" was the Lumière Autochrome, a glass plate product introduced in 1907. It was expensive and not sensitive enough for hand-held "snapshot" use. Film-based versions were introduced in the early 1930s and the sensitivity was later improved. These were "mosaic screen" additive color products, which used a simple layer of black-and-white emulsion in combination with a layer of microscopically small color filter elements. The resulting transparencies or "slides" were very dark because the color filter mosaic layer absorbed most of the light passing through. The last films of this type were discontinued in the 1950s, but Polachrome "instant" slide film, introduced in 1983, temporarily revived the technology.

"Color film" in the modern sense of a subtractive color product with a multi-layered emulsion was born with the introduction of Kodachrome for home movies in 1935 and as lengths of 35 mm film for still cameras in 1936. During the next several decades, color remained much more expensive than black-and-white and required much more light, factors which combined to delay its widespread adoption. Decreasing cost and increasing sensitivity gradually overcame these impediments. By the 1970s color film predominated and the use of black-and-white film was increasingly confined to low-light and "art" photography and other niche applications.

Effect on lens and equipment design[edit]

Photographic lenses and equipment are designed around the film to be used. Although the earliest photographic materials were sensitive only to the blue-violet end of the spectrum, partially color-corrected achromatic lenses were normally used, so that when the photographer brought the visually brightest yellow rays to a sharp focus, the visually dimmest but photographically most active violet rays would be correctly focused, too. The introduction of orthochromatic emulsions required the whole range of colors from yellow to blue to be brought to an adequate focus. Most plates and films described as orthochromatic or isochromatic were practically insensitive to red, so the correct focus of red light was unimportant; a red window could be used to view the frame numbers on the paper backing of roll film, as any red light which leaked around the backing would not fog the film; and red lighting could be used in darkrooms. With the introduction of panchromatic film the whole visible spectrum needed to be brought to an acceptably sharp focus. In all cases a color cast in the lens glass or faint colored reflections in the image were of no consequence as they would merely change the contrast a little. This was no longer acceptable when using color film. More highly corrected lenses for newer emulsions could be used with older emulsion types, but the converse was not true.

The current meanings of the terms "orthochromatic" and "isochromatic" evolved in the early 20th century. In the late 19th century, they were used interchangeably to mean simply "color-sensitized" for the purpose of producing more natural-looking black-and-white images. Various manufacturers favored either "orthochromatic" ("correct-colored") or "isochromatic" ("same-colored") on linguistic grounds, and some materials so described were, in fact, modestly sensitive to red light (e.g., the Edwards Isochromatic plate). The first plates described as "panchromatic" ("all-colored") were introduced, along with the word, by the Lumière Brothers in 1894 (not by Wratten and Wainwright, or Ilford, in 1906 as is commonly stated) and the new and explicitly all-encompassing term eventually came into generic use for distinguishing materials sensitized to all colors including red.

Types[edit]

Structure of silver bromide, the component of most photographic film that reacts with light.

There are several types of photographic film, including:

  • Print film, when developed, yields transparent negatives with the light and dark areas and colors (if color film is used) inverted to their opposites. This type of film is designed to be printed onto photographic paper, usually by means of an enlarger but in some cases by contact printing. The paper is then itself developed. The second inversion that results restores light, shade and color to their normal appearance. Color negatives incorporate an orange color correction mask that compensates for unwanted dye absorption and improves color accuracy in the prints. Although color processing is more complex and temperature-sensitive than black-and-white processing, the wide availability of commercial color processing and scarcity of service for black-and-white prompted the design of some black-and-white films which are processed in exactly the same way as standard color film.
  • Color reversal film produces positive transparencies, also known as diapositives, which are sometimes inspected with the aid of a magnifying loupe and a lightbox. If mounted in small metal, plastic or cardboard frames for use in a slide projector or slide viewer they are commonly called slides. Reversal film is often marketed as "slide film". Large-format color reversal sheet film is used by some professional photographers, typically to originate very-high-resolution imagery for digital scanning into color separations for mass photomechanical reproduction. Photographic prints can be produced from reversal film transparencies, but this process is usually more expensive and complex than printing from a negative.
  • Black-and-white reversal film exists but is very uncommon. Conventional black-and-white negative film can be reversal-processed to produce black-and-white slides, as by dr5 Chrome.[13] Although kits of chemicals for black-and-white reversal processing may no longer be available to amateur darkroom enthusiasts, an acid bleaching solution, the only unusual component which is essential, is easily prepared from scratch. Black-and-white transparencies may also be produced by printing negatives onto special positive print film, still available from some specialty photographic supply dealers.[14]

Creating an image[edit]

In order to produce a usable image, the film needs to be exposed properly. The amount of exposure variation that a given film can tolerate while still producing an acceptable level of quality is called its exposure latitude. Color print film generally has greater exposure latitude than other types of film. Additionally, because print film must be printed to be viewed, after-the-fact corrections for imperfect exposure are possible during the printing process.

The concentration of dyes or silver salts remaining on the film after development is referred to as optical density, or simply density; the optical density is proportional to the logarithm of the optical transmission coefficient of the developed film. A dark image on the negative is of higher density than a more transparent image.

Most films are affected by the physics of silver grain activation (which sets a minimum amount of light required to expose a single grain) and by the statistics of random grain activation by photons. The film requires a minimum amount of light before it begins to expose, and then responds by progressive darkening over a wide dynamic range of exposure until all of the grains are exposed and the film achieves (after development) its maximum optical density.

Over the active dynamic range of most films, the density of the developed film is proportional to the logarithm of the total amount of light to which the film was exposed, so the transmission coefficient of the developed film is proportional to a power of the reciprocal of the brightness of the original exposure. This effect is due to the statistics of grain activation: as the film becomes progressively more exposed, each incident photon is less likely to impact a still-unexposed grain, yielding the logarithmic behavior. A simple, idealized statistical model yields the equation density = 1 - ( 1 - k) light, where light is proportional to the number of photons hitting a unit area of film, k is the probability of a single photon striking a grain (based on the size of the grains and how closely spaced they are), and density is the proportion of grains that where hit by at least one photon.

If parts of the image are exposed heavily enough to approach the maximum density possible for a print film, then they will begin losing the ability to show tonal variations in the final print. Usually those areas will be considered overexposed and will appear as featureless white on the print. Some subject matter is tolerant of very heavy exposure; for example sources of brilliant light such as a light bulb or the sun generally appear best as a featureless white on the print.

Likewise, if part of an image receives less than the beginning threshold level of exposure, which depends upon the film's sensitivity to light—or speed—the film there will have no appreciable image density, and will appear on the print as a featureless black. Some photographers use their knowledge of these limits to determine the optimum exposure for a photograph; for one example, see the Zone System. Most automatic cameras instead try to achieve a particular average density.

Resolution[edit]

Film resolution is measured using lp/mm. Some films are able to resolve more lp/mm than others. Average is somewhere around 120 lp/mm, and can be much higher depending on design of the film and intended application. With regard to photographic film resolution as it relates to current day digital cameras: "A digital camera would have to be 156 megapixels to give you the same kind of detail as 35mm film." and "Large format 4x5" would be 95 x 120 mm, which is 11,400 sq mm, and 1026 megapixel, with full RGB data at each pixel. With 8x10 sheets or 203 x 254 mm you have 51,562 sq mm and 4640 megapixel, which is insane."[15][16] Resolution is not why film photographers shoot film, unlike their digital counter parts. Film is more complex than any single factor like resolution to quantify film's attributes completely.

Speed[edit]

Film speed describes a film's threshold sensitivity to light. The international standard for rating film speed is the ISO scale which combines both the ASA speed and the DIN speed in the format ASA/DIN. Using ISO convention film with an ASA speed of 400 would be labeled 400/27°. A fourth naming standard is GOST, developed by the Russian standards authority. See the film speed article for a table of conversions between ASA, DIN, and GOST film speeds.

Common film speeds include ISO 25, 50, 64, 100, 160, 200, 400, 800, 1600, 3200, and 6400. Consumer print films are usually in the ISO 100 to ISO 800 range. Some films, like Kodak's Technical Pan, are not ISO rated and therefore careful examination of the film's properties must be made by the photographer before exposure and development. ISO 25 film is very "slow", as it requires much more exposure to produce a usable image than "fast" ISO 800 film. Films of ISO 800 and greater are thus better suited to low-light situations and action shots (where the short exposure time limits the total light received). The benefit of slower film is that it usually has finer grain and better color rendition than fast film. Professional photographers of static subjects such as portraits or landscapes usually seek these qualities, and therefore require a tripod to stabilize the camera for a longer exposure. Photographing subjects such as rapidly moving sports or in low-light conditions, a professional will choose a faster film.

A film with a particular ISO rating can be push-processed, or "pushed", to behave like a film with a higher ISO, by developing for a longer amount of time or at a higher temperature than usual. More rarely, a film can be "pulled" to behave like a "slower" film. Pushing generally coarsens grain and increases contrast, reducing dynamic range, to the detriment of overall quality. Nevertheless, it can be a useful trade-off in difficult shooting environments, if the alternative is no usable shot at all.

Special films[edit]

Instant photography, as popularized by Polaroid, uses a special type of camera and film that automates and integrates development, without the need of further equipment or chemicals. This process is carried out immediately after exposure, as opposed to regular film, which is developed afterwards and requires additional chemicals. See instant film.

Films can be made to record non-visible ultraviolet (UV) and infrared (IR) radiation. These films generally require special equipment; for example, most photographic lenses are made of glass and will therefore filter out most ultraviolet light. Instead, expensive lenses made of quartz must be used. Infrared films may be shot in standard cameras using an infrared band- or long-pass filter, although the infrared focal point must be compensated for.

Exposure and focusing are difficult when using UV or IR film with a camera and lens designed for visible light. The ISO standard for film speed only applies to visible light, so visual-spectrum light meters are nearly useless. Film manufacturers can supply suggested equivalent film speeds under different conditions, and recommend heavy bracketing (e.g. with a certain filter, assume ISO 25 under daylight and ISO 64 under tungsten lighting). This allows a light meter to be used to estimate an exposure. The focal point for IR is slightly farther away from the camera than visible light, and UV slightly closer; this must be compensated for when focusing. Apochromatic lenses are sometimes recommended due to their improved focusing across the spectrum.

Film optimized for sensing X-ray radiation is commonly used for medical imaging by placing the subject between the film and a source of X-rays, without a lens, as if a translucent object were imaged by being placed between a light source and standard film. Unlike other types of film, X-ray film has a sensitive emulsion on both sides of the carrier material. This reduces the X-ray exposure for an acceptable image – a desirable feature in medical radiography. The film is usually placed in contact with a thin layer of lead which also enhances its sensitivity.

Film has a number of disadvantages as a scientific detector: it is difficult to calibrate for photometry, it is not re-usable, it requires careful handling (including temperature and humidity control) for best calibration, and the film must physically be returned to the laboratory and processed. Against this, photographic film can be made with a higher spatial resolution than any other type of imaging detector, and, because of its logarithmic response to light, has a wider dynamic range than most digital detectors. For example, Agfa 10E56 holographic film has a resolution of over 4,000 lines/mm—equivalent to a pixel size of 0.125 micrometers—and an active dynamic range of over five orders of magnitude in brightness, compared to typical scientific CCDs that might have pixels of about 10 micrometers and a dynamic range of 3-4 orders of magnitude.

DX codes[edit]

Film manufacturers commonly make film that is branded by other companies. Modern films have bar codes (DX codes) on the edge of the film which can be read by a bar code reader. This is because film is sometimes processed differently according to specifications of the film, determined by its manufacturer; the bar code is entered into the film processor before the film is developed or printed.

To establish the OEM, read the bar code printed on the cassette. Divide the long number by 16 and record the number before the decimal, then multiply the number after the decimal by 16, this could give you a result such as 18 and 2.

The first number is known as the PRODUCT (film manufacturer) and the second number as the MULTIPLIER (speed of the film ISO). In the previous example, 18 identifies 3M as the manufacturer and 2 means it is 200 ISO:

  • 3M = 18
  • Agfa = 17 or 49
  • Kodak = 80, 81, 82 or 88

Common sizes[edit]

See also: Film format

Manufactures and coating companies[edit]

Up to date as of 07-27-2015 (Still researching and need to add "coaters only" to the list).

In production[edit]

Processing, darkrooms, and scanning services[edit]

Scanning[edit]

Brands[edit]

  • Current list - List can be expanded via additional entries.

Re-branding sellers[edit]

(Need to add more to this list, as there are many more sellers that have re-branded in-house brand films.)

  • AgfaPhoto - Sells products made by Fuji and Harmon Technologies Ltd. under the AgfaPhoto brand.
  • Arista In-house brand for Freestyle Photo Online.
  • CineStill film Cine film from Kodak made for use in still photography and C-41 processing.
  • Rollei film - Sells products made by Agfa-Gevaert and others under the Rollei brand.
  • Lomography - An ecosystem designed to meet the needs of analogue film photographers worldwide.
  • Maco Distributor of film products.
  • Ultrafine In-house brand for the Photo Warehouse.

Out of production[edit]

Please note that though out of production, many of the recipes for these films live on, and can and have been revisited and reproduced via a current in-production film manufacture and/or coater. Sometimes, these film recipes are updated to produce a product unique for today's needs.

See also[edit]

References[edit]

  1. ^ http://www.bbc.com/news/magazine-20434270
  2. ^ http://www.lomography.com/about/history "The new site allows you to browse over 12,000,000 photos, read over 50,000 magazine articles and connect with over 1 million talented Lomographers from the world!".
  3. ^ http://www.calgaryherald.com/entertainment/theatre/generation+school+photographers+launch+magazine/7954464/story.html " a new generation of photographers have embraced traditional photography, lobbing around terms like wet plate, ambertype and Polaroid as if it were 1973, not 2013."
  4. ^ http://www.rbj.net/article.asp?aID=191108 "Kodak ended the first quarter—historically its worst quarter in terms of cash generation—with a cash balance of $1.4 billion, up $500 million from year-end 2011."
  5. ^ http://www.pdnonline.com/features/The-Future-of-Film-5631.shtml "Kodak’s competitors have also recently suggested that film remains a profitable business. One manufacturer, Lomography, is seeing substantial growth. - See more at: http://www.pdnonline.com/features/The-Future-of-Film-5631.shtml#sthash.NMlZ0W2s.dpuf"
  6. ^ http://www.techradar.com/news/photography-video-capture/cameras/lomography-film-sales-increasing-1057144 "Lomography: film sales increasing"
  7. ^ http://petapixel.com/2013/11/14/kodak-lomography-partner-vow-keep-film-photography-alive/ "Lo-fi photography specialist Lomography and Kodak Alaris, a U.K.-based offshoot of the one-time photography behemoth, recently announced a joint effort to boost photographic film manufacturing and sales."
  8. ^ https://www.kickstarter.com/projects/filmferrania/100-more-years-of-analog-film
  9. ^ http://www.thephoblographer.com/2015/04/23/manufacturers-talk-state-film-photography-industry/#.VbRb-_k4fCu
  10. ^ "Why Brand Building Is Important"
  11. ^ Karlheinz Keller et al. "Photography" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a20_001
  12. ^ http://www.kodak.com/global/en/corp/historyOfKodak/1878.jhtml
  13. ^ "dr5CHROME B&W reversal process information". 
  14. ^ Haist, Grant, Modern Photographic Processing.
  15. ^ http://istillshootfilm.org/post/114131916747/the-real-resolution-of-film-vs-digital?utm_content=buffer6cfd8&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer
  16. ^ http://kenrockwell.com/tech/film-resolution.htm
  17. ^ http://lavidaleica.com/content/fotokemika-ceases-production-affects-efkeadox

External links[edit]