Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Photographic Film shopping experience:
1. Compare - without doubt the biggest advantage that the Photographic Film offers shoppers today is the ability to compare thousands of Photographic Film at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Photographic Film? Wrong! If the Photographic Film is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Photographic Film then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Photographic Film? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Photographic Film and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Photographic Film wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Photographic Film then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Photographic Film site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Photographic Film, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Photographic Film, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
125/22°.
This article is mainly concerned with still photography film. For motion picture film, please see film stock.
Photographic film is a sheet of
plastic (polyester,
nitrocellulose or cellulose acetate) coated with an emulsion containing light-sensitive
silver halide salts (bonded by gelatin) with variable crystal sizes that determine the sensitivity, contrast and Image resolution of the film. When the emulsion is sufficiently exposed to light (or other forms of electromagnetic radiation such as X-rays), it forms a
latent image (invisible) image. Chemical processes can then be applied to the film to create a visible image, in a process called film developing.
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 block light and appear as the black part of the film
negative.
Color film uses at least three layers. Dyes, which adsorb to the surface of the silver salts, make the crystals sensitive to different colors. Typically the blue-sensitive layer is on top, followed by the green and red layers. 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. This leaves behind only the formed color dyes, which combine to make up the colored visible image.
Newer color films, like Kodacolor (still photography), have as many as 12 emulsion layers, with upwards of 20 different chemicals in each layer.
Because photographic film is widespread in the production of motion pictures, or
film, these are also known as
films.
Film basics
There are two primary types of photographic film:
- Print film, when developed, turns into a Negative (photography) with the colors (or black and white values, in black and white film) inverted. This type of film must be "printed"—either projected through a lens or placed in contact—to photographic paper in order to be viewed as intended. Print films are available in both black-and-white and Color print film.
- Color reversal film after development is called a transparency (photography) and can be viewed directly using a loupe or slide projector. Reversal film mounted with plastic or cardboard for projection is often called a slide. It is also often marketed as "slide" film. This type of film is often used to produce film scanner or color separations for mass-market printing. Photographic prints can be produced from reversal film, but the process is expensive and not as simple as that for print film. Black and white reversal film exists, but is uncommon—one of the reasons reversal films are popular among professional photographers is the fact that they are generally superior to print films with regards to color reproduction. (Conventional black and white negative stock can be reversal-processed, to give "black & white slides", and kits are available to enable this to be done by home-processors. As indicated by Grant Haist's published book Modern Photographic Processing, B&W transparencies can be produced from most all B&W films.)
In order to produce a usable image, the film needs to be
exposure (photography) 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 (mathematics) of the
Reciprocal (mathematics) of the brightness of the original exposure. This 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.
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 deemed to be overexposed and will appear as featureless white on the print. Some subject matter is tolerant of very heavy exposure; brilliant light sources like a bright lightbulb, or the sun, included in the image 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.
Film speed
Film speed describes a film's threshold sensitivity to light. The international standard for rating film speed is the International Standards Organization scale which combines both the
American Standards Association 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°. ASA is by far the more popular of the available standards, especially with newer equipment, and is often used interchangeably with the term ISO, although DIN retains popularity in Germany. The prevalence of ASA is reflected in film packaging which normally boldly states the ASA speed of the film on the box, with the full ISO speed printed in smaller type on the reverse or base. 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, and 3200. 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 (photography) 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 films is that it usually has finer grain and better color rendition than fast film. Professional photography with 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.
Grain size refers to the size of the silver crystals in the emulsion. The smaller the crystals, the finer the detail in the photo and the slower the film.
A film with a particular ISO rating can be
Push processing to behave like a film with a higher ISO. In order to do this, the film must be developed for a longer amount of time or at a higher temperature than usual. This procedure is usually only performed by photographers who do their own development or professional-level photofinishers. More rarely, a film can be
pulled to behave like a "slower" film.
History of film
Hurter & Driffield began pioneering work on the
sensitometry of film in 1876 onwards. Their work enabled the first quantitative measure of film speed to be devised.
Early photography in the form of
daguerreotypes did not use film at all.
Eastman Kodak developed the first flexible photographic film in 1885. This original "film" was coated on paper. The first transparent plastic film was produced in 1889. Before this, glass photographic plates were used, which were far more expensive and cumbersome, albeit also of better quality. The first photographic film was made from highly flammable
nitrocellulose with camphor as a
plasticizer (celluloid). Beginning in the
1920s, nitrate film was replaced with cellulose acetate or "safety film". This changeover was not completed until
1933 for
X-ray films (where its flammability hazard was most acute) and for motion picture film until 1951.
From the end of the 20th century digital photography became practical, and by 2000 was replacing film as the preferred photographic medium for many applications.
Spectral sensitivity
The first films were sensitive to blue light only. Orthochromatic film sensitive to the visual spectrum from green to blue was introduced in 1879 and was dominant until the mod-1920s, when
panchromatic film sensitive to the entire visual spectrum, became standard. All of these films were used to produce black and white images, regardless of spectral sensitivity.
Experiments with
color photography were first made in 1861, but generally usable emulsions only became available in the 1930s. After the Second World War much progress was made, and color became used for the overwhelming majority of photographs.
Effect on lens and equipment design
Photographic lenses and equipment are designed around the film to be used. The earliest lenses needed to focus blue light only. The introduction of orthochromatic film required the spectrum from green to blue to be brought to the same focus. A red window could be used to view frame numbers of rollfilm; any red light which leaked beyond the film backing would not fog the film; and red lighting could be used in darkrooms. With the introduction of panchromatic film the whole visual spectrum needed to be brought to the same 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 with the introduction of color film. More highly corrected lenses for newer emulsions could be used with older emulsion types, but the converse was not true.
The
photographic filter used were different for the different film types.
The progression of lens design for later emulsions is of practical importance when considering the use of old lenses, still often used on large-format equipment; a lens designed for orthochromatic film may have visible defects with a color emulsion; a lens for panchromatic film will be better but not as good as later designs.
While color processing is more complex and temperature-sensitive than for monochromatic film, the great popularity of color and almost disappearance of monochrome prompted the design of monochromatic film which is processed in exactly the same way as a standard color film.
Special films
Instant photography, as popularised by Polaroid Corporation, 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 light
ultraviolet (UV) and
infrared (IR)
electromagnetic spectrum. 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 (optics), 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 father away from the camera than visible light, and UV slightly closer; this must be compensated for when focussing. 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.
Film optimized for sensing X-rays and for
gamma rays is sometimes used for radiation
dosimetry and
personal monitoring.
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 micrometres—and an active dynamic range of over five orders of magnitude in brightness, compared to typical scientific Charge-coupled devices that might have pixels of about 10 micrometres and a dynamic range of 3-4 orders of magnitude.
Special films are used for the long exposures required by
astrophotography.
Common sizes of film
- 135 film (popularly known as "35 mm")
- Advanced Photo System (Advanced Photo System)
- 110 film
- 126 film
- 127 film
- 120 film/220 (for use in medium format photography)
- Sheet film (for use in large format photography)
- Disc film Obsolete format used in disc system cameras
- Film stock: 8 mm, 16 mm, 35 mm and 70 mm
Companies that manufacture photographic film
- Agfa-Gevaert
- Bergger (European company composed of former Guilleminot employees.)
- Efke
- Foma
- Forte
- Ferrania
- Fujifilm
- Perutz
- Polaroid Corporation
- ProClick
- Solaris (Ferrania)
- Svema
- Tasma
- Tura
Film manufacturers commonly make film that is branded by other companies. Modern films have bar 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 computer printer before the film is printed.
To establish the
Original equipment manufacturer, 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
Notable films
- Kodak Kodachrome is one of the oldest slide films still being produced and is known for its long archive stability.
- Fuji Velvia, also a slide film, is known for its high contrast and hyper-saturated colors. It is popular with landscape and nature photographers.
- Both Kodak T-max p3200 and Ilford Delta 3200 are B&W films with very wide exposure latitude. They are rated at roughly ISO 1000, but can be Push processing to ISO 3200 or higher. Rated speeds of as high as ISO 25,000 have been obtained.
- Kodak Technical Pan, which has now been discontinued, is a widely acclaimed slow black and white film. With a speed of ISO 25, it gave clear, incredibly fine-grained results. It has now become somewhat of a commodity item among photographers as it is very limited, and very little if any stock remains at photographic suppliers.
See also
References
- Modern Photographic Processing: Grant Haist
- APUG (traditional photography 'analog' forums)
- dr5.com (B&W reversal)
- British Journal of Photography
125/22°.
This article is mainly concerned with still photography film. For motion picture film, please see film stock.
Photographic film is a sheet of plastic (polyester,
nitrocellulose or
cellulose acetate) coated with an
emulsion containing light-sensitive silver halide salts (bonded by
gelatin) with variable crystal sizes that determine the sensitivity, contrast and
Image resolution of the film. When the emulsion is sufficiently exposed to
light (or other forms of
electromagnetic radiation such as
X-rays), it forms a
latent image (invisible) image. Chemical processes can then be applied to the film to create a visible image, in a process called film developing.
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 block light and appear as the black part of the film
negative.
Color film uses at least three layers. Dyes, which adsorb to the surface of the silver salts, make the crystals sensitive to different colors. Typically the blue-sensitive layer is on top, followed by the green and red layers. 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. This leaves behind only the formed color dyes, which combine to make up the colored visible image.
Newer color films, like Kodacolor (still photography), have as many as 12 emulsion layers, with upwards of 20 different chemicals in each layer.
Because photographic film is widespread in the production of motion pictures, or film, these are also known as
films.
Film basics
There are two primary types of photographic film:
- Print film, when developed, turns into a Negative (photography) with the colors (or black and white values, in black and white film) inverted. This type of film must be "printed"—either projected through a lens or placed in contact—to photographic paper in order to be viewed as intended. Print films are available in both black-and-white and Color print film.
- Color reversal film after development is called a transparency (photography) and can be viewed directly using a loupe or slide projector. Reversal film mounted with plastic or cardboard for projection is often called a slide. It is also often marketed as "slide" film. This type of film is often used to produce film scanner or color separations for mass-market printing. Photographic prints can be produced from reversal film, but the process is expensive and not as simple as that for print film. Black and white reversal film exists, but is uncommon—one of the reasons reversal films are popular among professional photographers is the fact that they are generally superior to print films with regards to color reproduction. (Conventional black and white negative stock can be reversal-processed, to give "black & white slides", and kits are available to enable this to be done by home-processors. As indicated by Grant Haist's published book Modern Photographic Processing, B&W transparencies can be produced from most all B&W films.)
In order to produce a usable image, the film needs to be
exposure (photography) 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 (mathematics) of the Reciprocal (mathematics) of the brightness of the original exposure. This 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.
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 deemed to be overexposed and will appear as featureless white on the print. Some subject matter is tolerant of very heavy exposure; brilliant light sources like a bright lightbulb, or the sun, included in the image 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.
Film speed
Film speed describes a film's threshold sensitivity to light. The international standard for rating film speed is the International Standards Organization scale which combines both the
American Standards Association 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°. ASA is by far the more popular of the available standards, especially with newer equipment, and is often used interchangeably with the term ISO, although DIN retains popularity in Germany. The prevalence of ASA is reflected in film packaging which normally boldly states the ASA speed of the film on the box, with the full ISO speed printed in smaller type on the reverse or base. 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, and 3200. 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 (photography) 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 films is that it usually has finer grain and better color rendition than fast film. Professional photography with 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.
Grain size refers to the size of the silver crystals in the emulsion. The smaller the crystals, the finer the detail in the photo and the slower the film.
A film with a particular ISO rating can be
Push processing to behave like a film with a higher ISO. In order to do this, the film must be developed for a longer amount of time or at a higher temperature than usual. This procedure is usually only performed by photographers who do their own development or professional-level photofinishers. More rarely, a film can be
pulled to behave like a "slower" film.
History of film
Hurter & Driffield began pioneering work on the
sensitometry of film in 1876 onwards. Their work enabled the first quantitative measure of film speed to be devised.
Early photography in the form of
daguerreotypes did not use film at all.
Eastman Kodak developed the first flexible photographic film in 1885. This original "film" was coated on paper. The first transparent plastic film was produced in 1889. Before this, glass photographic plates were used, which were far more expensive and cumbersome, albeit also of better quality. The first photographic film was made from highly flammable nitrocellulose with
camphor as a
plasticizer (
celluloid). Beginning in the 1920s, nitrate film was replaced with cellulose acetate or "safety film". This changeover was not completed until
1933 for
X-ray films (where its flammability hazard was most acute) and for motion picture film until 1951.
From the end of the 20th century
digital photography became practical, and by 2000 was replacing film as the preferred photographic medium for many applications.
Spectral sensitivity
The first films were sensitive to blue light only.
Orthochromatic film sensitive to the
visual spectrum from green to blue was introduced in 1879 and was dominant until the mod-1920s, when
panchromatic film sensitive to the entire visual spectrum, became standard. All of these films were used to produce black and white images, regardless of spectral sensitivity.
Experiments with color photography were first made in 1861, but generally usable emulsions only became available in the 1930s. After the
Second World War much progress was made, and color became used for the overwhelming majority of photographs.
Effect on lens and equipment design
Photographic lenses and equipment are designed around the film to be used. The earliest lenses needed to focus blue light only. The introduction of orthochromatic film required the spectrum from green to blue to be brought to the same focus. A red window could be used to view frame numbers of rollfilm; any red light which leaked beyond the film backing would not fog the film; and red lighting could be used in darkrooms. With the introduction of panchromatic film the whole visual spectrum needed to be brought to the same 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 with the introduction of color film. More highly corrected lenses for newer emulsions could be used with older emulsion types, but the converse was not true.
The
photographic filter used were different for the different film types.
The progression of lens design for later emulsions is of practical importance when considering the use of old lenses, still often used on large-format equipment; a lens designed for orthochromatic film may have visible defects with a color emulsion; a lens for panchromatic film will be better but not as good as later designs.
While color processing is more complex and temperature-sensitive than for monochromatic film, the great popularity of color and almost disappearance of monochrome prompted the design of monochromatic film which is processed in exactly the same way as a standard color film.
Special films
Instant photography, as popularised by
Polaroid Corporation, 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 light
ultraviolet (UV) and
infrared (IR) electromagnetic spectrum. 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 (optics), 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 father away from the camera than visible light, and UV slightly closer; this must be compensated for when focussing.
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.
Film optimized for sensing X-rays and for
gamma rays is sometimes used for radiation dosimetry and
personal monitoring.
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 micrometres—and an active dynamic range of over five orders of magnitude in brightness, compared to typical scientific
Charge-coupled devices that might have pixels of about 10 micrometres and a dynamic range of 3-4 orders of magnitude.
Special films are used for the long exposures required by
astrophotography.
Common sizes of film
Companies that manufacture photographic film
- Agfa-Gevaert
- Bergger (European company composed of former Guilleminot employees.)
- Efke
- Foma
- Forte
- Ferrania
- Fujifilm
Film manufacturers commonly make film that is branded by other companies. Modern films have bar 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 computer printer before the film is printed.
To establish the
Original equipment manufacturer, 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
Notable films
- Kodak Kodachrome is one of the oldest slide films still being produced and is known for its long archive stability.
- Fuji Velvia, also a slide film, is known for its high contrast and hyper-saturated colors. It is popular with landscape and nature photographers.
- Both Kodak T-max p3200 and Ilford Delta 3200 are B&W films with very wide exposure latitude. They are rated at roughly ISO 1000, but can be Push processing to ISO 3200 or higher. Rated speeds of as high as ISO 25,000 have been obtained.
- Kodak Technical Pan, which has now been discontinued, is a widely acclaimed slow black and white film. With a speed of ISO 25, it gave clear, incredibly fine-grained results. It has now become somewhat of a commodity item among photographers as it is very limited, and very little if any stock remains at photographic suppliers.
See also
References
- Modern Photographic Processing: Grant Haist
- APUG (traditional photography 'analog' forums)
- dr5.com (B&W reversal)
- British Journal of Photography
Photographic film - Wikipedia, the free encyclopedia
Photographic film is a sheet of plastic (polyester, nitrocellulose or cellulose acetate) coated with an emulsion containing light-sensitive silver halide salts (bonded by gelatin ...
Photographic Film
This page is no longer being maintained but is left here as a service to those who have links to it.
FUJIFILM Europe | Photographic Film
Velvia 100 Professional (RVP 100) (Professional) The Velvia 100 (RVP 100) Professional uses new technologies which make it possible to achieve a finer grain and a doubling in ...
Paterson Photographic - Darkroom Equipment, Film developing tanks ...
Worldwide Paterson is best known for the high quality darkroom equipment it manufactures here in the UK. In the late 80s it also took over the manufacture of Benbo Tripods and has ...
Celluloid Photographic Film
As soon as the 'gelatin dry plate' process of photography had replaced the 'wet collodion' process in the 1870s, the search was on ...
Film from Firstcall Photographic
Sigma EF-530 DG Super Flashgun, Pentax Staff Review: “Extracts from Review/Test by John Clements, British Journal of Photography, 12 September 2007:
Supreme Imports - Products - Photographic - Film
Since its establishment in 1970 Supreme Imports has grown into the largest branded battery distributor in the world. We now service over 20% of the UK market and distribute a ...
R & K Photographic transparency scanning | High resolution 35mm film ...
Offers scanning of 35mm slides, roll films, negatives, transparencies, Xpan, and medium formats including 6x4.5 to 6x9. Offering services internationally. Located in Penryn ...
Bolton Colour Lab pro photographic printers and online digital photo ...
BCL professional photographic printing and online digital photo print lab services - printers of film and digital photography inc pro online digital photo printing service large ...
Photographic, Optical, projectors, cameras, film, lenses, prisms
Photographic, Optical, projectors, cameras, film, lenses, prisms ... Our Photographic department at Nottingham has now CLOSED. We do receive Cameras from the MoD occasionally and ...