Infrared photography
1054632
225167567
2008-07-12T06:49:07Z
Thijs!bot
1392310
robot Adding: [[ja:赤外線写真]]
<!-- dirty way to present two images in a floating thumbnail frame -->
<div class="thumb tright">
<div class="thumbinner" style="width:202px;" >
[[Image:Tree example IR.jpg|200px]]
[[Image:Tree example VIS.jpg|200px]]
<div class="thumbcaption">
''Top:'' tree photographed in the near [[infrared]] range. ''Bottom:'' same tree in the [[Visible spectrum|visible part of the spectrum]].
</div>
</div>
</div>
[[Image:Minnesota Lock and Dam 1 006-062-02-1994.jpg|thumb|Infrared image of the [[Mississippi River]] crossed by a bridge and a dam, between red foliage on left, and blue parking lots and buildings on right]]
In '''infrared photography''', the [[film]] or [[image sensor]] used is sensitive to [[infrared]] light. The part of the [[visible spectrum|spectrum]] used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of [[thermal imaging]]. [[Wavelength]]s used for [[photography]] range from about 700 [[nanometre|nm]] to about 900 nm. Usually an "[[infrared filter]]" is used; this lets infrared (IR) light pass through to the [[camera]], but blocks all or most of the visible light spectrum (the filter thus looks black or deep red).
When these [[band-pass filter|filters]] are used together with infrared-sensitive film or sensors, very interesting "[[in-camera effect]]s" can be obtained; [[false-color]] or [[black-and-white]] images with a dreamlike or sometimes lurid appearance known as the "Wood Effect."
The effect is mainly caused by [[foliage]] (such as tree leaves and grass) strongly reflecting in the same way visible light is reflected from [[snow]]. There is a small contribution from chlorophyll [[fluorescence]], but this is extremely small and is not the real cause of the brightness seen in infrared photographs.
The other attributes of infrared photographs include very dark skies and penetration of atmospheric haze, caused by reduced [[Rayleigh scattering]] and [[Mie scattering]], respectively, compared to visible light. The dark skies, in turn, result in less infrared light in shadows and dark reflections of those skies from water, and clouds will stand out strongly. These wavelengths also penetrate a few millimeters into skin and give a milky look to portraits, although eyes often look black.
==History==
Until the early 1900s, infrared photography was not possible because [[silver halide]] emulsions are not sensitive to infrared radiation without the addition of a dye to act as a color sensitizer<ref>{{cite web
| url = http://www.cheresources.com/photochem.shtml
| title = Chemistry of Photography
| accessdate = 2006-11-28
}}</ref>. The first infrared photograph was published in 1910 by [[Robert W. Wood]], who discovered the unusual color effects that now bear his name<ref>{{cite web
| url = http://msp.rmit.edu.au/Article_04/06.html
| title = Pioneers of Invisible Radiation Photography - Professor Robert Williams Wood
| accessdate = 2006-11-28
}}</ref>. Wood's photographs were taken on [[experimental film]] that required very long exposures; thus, most of his work focused on landscapes.
Infrared-sensitive [[photographic plate]]s were developed in the United States during [[World War I]] for improved [[aerial photography]].<ref>''Annual Report of the Director Bureau of Standards to the Secretary of Commerce for the Fiscal Year Ended June 30, 1919'' U. S. Govt. Print. Off., United States National Bureau of Standards, 1919.</ref>
False-color infrared photography became widely practiced with the introduction of Kodak Ektachrome Infrared Aero Film, Type 8443, in the 1960s.
Infrared photography became popular with a number of 1960s recording artists, because of the unusual results; [[Jimi Hendrix]], [[Donovan]], [[Frank Zappa]] and the [[Grateful Dead]] all issued albums with infrared cover photos. The unexpected colors and effects that infrared film can produce fit well with the [[psychedelic]] aesthetic that emerged in the late 1960s. Infrared photography can easily look gimmicky, but photographers such as [[Elio Ciol]] have made subtle use of black-and-white infrared-sensitive film.
[[Image:Bnb train 2 bnw.jpg|thumb|A near-infrared photograph of a [[Ringling Bros. and Barnum & Bailey Circus|Ringling Brothers]]' train idling near MIT in Cambridge, Massachusetts]]
==Focusing infrared==
Most [[manual focus]] 35mm SLR and [[medium format (film)|medium format]] SLR lenses have a red dot, line or diamond, often with a red "R" called the infrared index mark, that can be used to achieve proper infrared focus; many autofocus lenses no longer have this mark. When a [[Single-lens reflex camera|single-lens reflex]] (SLR) camera is fitted with a filter that is opaque to visible light, the reflex system becomes useless for both framing and focusing, and a tripod is necessary for composition without the filter before the exposure is done with the filter attached. A sharp infrared photograph can be done with a tripod, a narrow aperture (like {{f/|22}}) and a slow [[shutter speed]] without focus compensation, however wider apertures like {{f/|2.0}} can produce sharp photos only if the lens is meticulously refocused to the infrared index mark, and only if this index mark is the correct one for the filter and film in use.
Most [[apochromat]]ic ('APO') lenses do not have an Infrared index mark and do not need to be refocused for the [[Infrared spectroscopy|infrared spectrum]] because they are already optically corrected into the near-infrared spectrum. [[Catadioptric]] lenses do not require this adjustment because [[mirror]]s do not suffer from [[chromatic aberration]].
[[Zoom lens]]es may scatter more light through their more complicated optical systems than [[prime lens]]es, that is, lenses of fixed focal length; for example, an infrared photo taken with a 50mm prime lens may look more contrasty than the same image taken at 50mm with a 28–80 zoom.
Some lens manufacturers such as Leica never put IR index marks on their lenses. The reason for this is because any index mark is only valid for one particular IR filter and film combination, and may lead to user error. Even when using lenses with index marks, focus testing is advisable as there may be a large difference between the index mark and the [[subject plane]].
==Film cameras==
[[Image:fogged hienegs.png|thumb|left|Infrared negatives fogged by the frame counter of a [[Minolta Maxxum 4]].]]
Many conventional cameras can be used for infrared photography, where infrared is taken to mean light of a wavelength only slightly longer than that of visible light. Photography of rather longer wavelengths is normally termed [[thermography]] and requires special equipment.
With some patience and ingenuity, most film cameras can be used. However, some cameras of the 1990s that used [[135 film|35mm film]] have infrared sprocket-hole sensors that can fog infrared film (their manuals may warn against the use of infrared film for this reason). Other film cameras are not completely opaque to infrared light.
{{-}}
===Black-and-white infrared film===
Black-and-white infrared negative films are sensitive to wavelengths in the 700 to 900 nm [[Near infrared spectroscopy|near infrared spectrum]], and most also have a sensitivity to blue light wavelengths. The notable halation effect or glow often seen in the highlights of infrared photographs is an artifact of [[Kodak]] High Speed Infrared (HIE) black-and-white [[Negative (photography)|negative film]] and not an artifact of infrared light. The glow or blooming is caused by the absence of an anti-halation layer on the back side of Kodak HIE film, this results in a scattering or blooming around the highlights that would usually be absorbed by the anti-halation layer in conventional films.
[[Image:Rudin-house.jpg|thumb|450px|[[Frank Lloyd Wright]]'s Rudin House: panchromatic film on the left, infrared on the right]]
The majority of black-and-white infrared art, landscape, and [[wedding photography]] is done using orange (15 or 21), red (23, 25, or 29) or visually opaque (72) filters over the lens to block the blue visible light from the exposure. The intent of filters in black-and-white infrared photography is to block blue wavelengths and allow infrared to pass through. Without filters, infrared negative films look much like conventional negative films because the blue sensitivity lowers the contrast and effectively counteracts the infrared look of the film. Some photographers use orange or red filters to allow slight amounts of blue wavelengths to reach the film, and thus lower the contrast. Very dark-red (29) filters block out almost all blue, and visually opaque (70, 89b, 87c, 72) filters block out all blue and also visible-red wavelengths, resulting in a more pure-infrared photo that usually looks more contrasty.
Certain infrared-sensitive films like Kodak HIE must only be loaded and unloaded in total darkness. Infrared black-and-white films require special development times but development is usually achieved with standard black-and-white film developers and chemicals (like D-76). Kodak HIE film has a [[polyester]] [[film base]] that is very stable but extremely easy to scratch, therefore special care must be used in the handling of Kodak HIE throughout the development and printing/scanning process to avoid damage to the film.
As of November 2, 2007, "KODAK is preannouncing the discontinuance" of HIE Infrared 35mm film stating the reasons that, "Demand for these products has been declining significantly in recent years, and it is no longer practical to continue to manufacture given the low volume, the age of the product formulations and the complexity of the processes involved." see notice: http://www.kodak.com/global/en/professional/products/films/discontinuedNotice.jhtml?id=0.2.26.14.25&lc=en
At the time of this notice, HIE Infrared 135-36 was available at a street price of around $12.00 a roll at US mail order outlets.
Arguably the greatest obstacle to infrared film photography has been the increasing difficulty of obtaining infrared-sensitive film. However despite the discontinuance of HIE, other newer infrared sensitive emulsions from EFKE, ROLLEI, and ILFORD are still available, but these formulations have differing sensitivity and specifications from the venerable KODAK HIE that has been around for at least two decades. Some of these infrared films are available in 120 and larger formats as well as 35mm, which adds flexibility to their application. With the discontinuance of Kodak HIE, Efke's IR820 film has become the only IR film on the market with good sensitivity beyond 750nm, the Rollei film does extend beyind 750nm but IR sensitivity falls of very rapidly.
{{-}}
===Color infrared film===
[[Image:Color infrared SFOSEAYYZ-tree.jpg|thumb|right|An example of color infrared.]]Color infrared [[reversal film|transparency films]] have three sensitized layers that, because of the way the dyes are coupled to these layers, reproduce infrared as red, red as green, and green as blue. All three layers are sensitive to blue so the film must be used with a -blue (''i.e.'', yellow) filter. The health of foliage can be determined from the relative strengths of green and infrared light reflected; this shows in color infrared as a shift from red (healthy) towards magenta (unhealthy). Early color infrared films were developed in the older [[E-4 process]], but Kodak later manufactured a color transparency film that could be developed in standard [[E-6 process|E-6]] chemistry, although more accurate results were obtained by developing using the AR-5 process. In general, color infrared does not need to be loaded in total darkness (despite what it said on the can), or refocused to the infrared index mark on the lens.
In 2007 Kodak announced that production of the 35mm version of their color infrared film (Ektachrome Professional Infrared/EIR) would cease as there was insufficient demand. It is assumed that the 70mm Aerographic format will continue.
There is no currently available digital camera that will produce the same results as Kodak color infrared film although the equivalent images can be produced by taking two exposures, one infrared and the other full-color, and combining in [[post-production]].
==Digital cameras==
[[Image:SD10 IR Bending Tree.jpg|thumb|right|250px|Bending Cypress: infrared shot by [[Sigma SD10]] with B+W 093 filter, ISO 100, {{f/|8}}, 1/160 s. Photo by Seng P. Merrill]]
[[Digital camera]] sensors are inherently sensitive to infrared light, which would interfere with the normal photography by confusing the autofocus calculations or softening the image (because infrared light is focused differently than visible light), or oversaturating the red channel. Also, some clothing is transparent in the infrared, leading to unintended (at least to the manufacturer) uses of [[video camera]]s.<ref name="nightshot">{{cite press release
| title = Ultra-Personal Sony Handycam
| publisher = Reuters wire service
| date = [[1998-08-12]]
| accessdate = 2007-02-09
| url = http://www.deadmedia.org/notes/38/380.html}}</ref> Thus, to improve image quality and protect privacy, many digital cameras employ infrared [[blocker]]s. Depending on your subject matter, infrared photography may not be practical with these cameras because the exposure times become overly long, often in the range of 30 seconds, creating [[Noise (physics)|noise]] and [[motion blur]] in the final image. However, for some subject matter the long exposure does not matter or the motion blur effects actually add to the image. Some lenses will also show a 'hot spot' in the centre of the image as their coatings are optimised for visible light and not for IR.
An alternative method of digital [[Single-lens reflex camera|SLR]] infrared photography is to remove the infrared blocker in front of the CCD and replace it with a filter that removes visible light. This filter is behind the mirror, so the camera can be used normally - handheld, normal shutter speeds, normal composition through the viewfinder, and focus, all work like a normal camera. Metering works but is not always accurate because of the difference between visible and infrared reflection.<ref>[http://www.jimchenphoto.com/digitalirfaq.html Digital Infrared at Jim Chen Photography]</ref> When the IR blocker is removed, many lenses which did display a hotspot cease to do so, and become perfectly usable for infrared photography.
Since the [[Bayer filter]]s in most digital cameras absorb a significant fraction of the infrared light, these cameras are sometimes not very sensitive as infrared cameras and can sometimes produce false colors in the images. An alternative approach is to use a [[Foveon X3 sensor]], which does not have absorptive filters on it; the [[Sigma SD10]] DSLR has a removable IR blocking filter and dust protector, which can be simply omitted or replaced by a deep red or complete visible light blocking filter. The [[Sigma SD14]] has an IR/UV blocking filter that can be removed/installed without tools. The result is a very sensitive digital IR camera.
[[Image:Nikau-IR.jpg|thumb|left|200px|A [[Nikau]] palm against a clear, sunny sky shows the high contrast that is often typical of outdoors infrared photography.]] Several [[Sony]] cameras have the so-called Night Shot facility, which physically moves the blocking filter away from the light path, which makes the cameras very sensitive to infrared light. Soon after its development, this facility was 'restricted' by Sony to make it difficult for people to take photos that saw through clothing<ref name="nightshot"/>. To do this the iris is opened fully and exposure duration is limited to long times of more than 1/30 second or so. It is possible to shoot infrared but neutral density filters must be used to reduce the camera's sensitivity and the long exposure times mean that care must be taken to avoid camera-shake artefacts.
[[Image:FiveDollarBillInfrared.jpg|thumb|250px|right|The reverse of the [[United States five-dollar bill]] has two rectangular strips that are blanked out when viewed in the infrared spectrum, as seen in this image taken by an infrared camera.]]
[[Fujifilm|Fuji]] have produced digital cameras for use in [[forensic]] criminology and medicine which have no infrared blocking filter. The first camera, designated the S3 PRO UVIR, also had extended [[ultraviolet]] sensitivity (digital sensors are usually less sensitive to UV than to IR). Optimum UV sensitivity requires special lenses, but ordinary lenses usually work well for IR. In 2007, [[Fujifilm|FujiFilm]] introduced a new version of this camera, based on the Nikon D200/ FujiFilm S5 called the IS Pro, also able to take Nikon lenses. Fuji had earlier introduced a non-SLR infrared camera, the IS-1, a modified version of the FujiFilm [[List of Fujifilm FinePix cameras|FinePix]] S9100. Unlike the S3 PRO UVIR, the IS-1 does not offer UV sensitivity.
[[Satellite]] sensors and [[thermographic camera]]s are sensitive to longer wavelengths of infrared, and use a variety of technologies which may not resemble common camera or filter designs. In particular, they often require cooling, since at these wavelengths, and [[room temperature]], all objects (including the camera body, the optics, and the detector itself) are glowing all the time (see [[thermal radiation]]).
[[Phase One]] [[digital camera back]]s can be ordered in an infrared modified form. The P45+ IR model is 39 megapixels and captures in 16 bit allowing for more highlight and shadow detail. Infrared Photography taken with this back rivals the quality of 8x10 infrared film.
<ref>{{cite web
| url = http://www.captureintegration.com/2008/06/09/p45-ir/
| title = Phase One P45+ IR
| accessdate = 2008-7-2
}}</ref>
== Notes ==
{{Reflist}}
== See also ==
* [[Thermographic camera]]
* [[Ultraviolet photography]]
== External links ==
{{External links}}
*{{dmoz|Arts/Photography/Techniques_and_Styles/Infrared}}
*[http://nikongear.com/smf/index.php?board=57.0 Infra-red gallery and discussion forum]
*[http://www.epfarms.org/~coffeebean/holly/enter.htm Infrared Photography Gallery] Holly Gollnick displays infrared photos taken in B&W and in digital false-color. (All filters 720nm - 900nm)
*[http://www.naturfotograf.com/UV_IR_rev00.html All you ever wanted to know about digital UV and IR photography, but could not afford to ask]
*[http://areallygoodname.com/2007/06/10/infrared-photography/ Home Made Infrared Camera]
*[http://www.dimagemaker.com/specials/digitalir/digitalir.php Digital infrared explanations, camera tests, conversion details and competition results]
*[http://www.dpfwiw.com/ir.htm Jeremy McCreary's infrared (IR) basics for digital photographers]
*Gisle Hannemyr's [http://hannemyr.com/photo/ir.html Digital Infrared Resource Page] will help you decide if your digital camera is IR-sensitive, and more
*[http://www.kleptography.com/notes-irconvert.htm Conversion instructions for the Canon G1]
*[http://nature-photography-central.com/surreal_photos.html Nature Photography Central - Digital IR tutorials for Nikon D70]
*[http://www.lifepixel.com/ Digital infrared do it yourself conversion tutorials, services and infrared photo manipulation videos]
*[http://www.xrez.com/gallery/zion/xRez_zion.html Infrared, gigapixel, spherical panorama]
*[http://www.infraredphoto.eu/Site/BillionPixel.html The Billion Infrared Pixel Image] Large-scale stitching and IR photography
*[http://www.infraredphoto.eu Digital Infrared Photography] An introductory two-part article that also covers seldom discussed topics (e.g., diffraction, mirror lenses, polarizing filters, IR flash photography, etc).
*[http://www.galleryhahn.com/gallery .:: GalleryHahn.com ::.] A Beautiful Infrared Gallery by a the German photographer Philip Hahn, as well as some of his other work.
*[http://www.myinfrared.com MyInfrared.com] Online digital infrared photography gallery.
*[http://www.tarquinius.de tarquinius.de] EIR Color Infrared Film in Medium Format.
*[http://www.ewongbusiness.com/mc B&W Infrared Gallery] B&W Infrared Gallery.
[[Category:Photography by genre]]
[[Category:Infrared imaging]]
[[de:Infrarotfotografie]]
[[es:Fotografía infrarroja]]
[[id:Fotografi inframerah]]
[[ja:赤外線写真]]
[[sk:Infračervená fotografia]]
[[sv:Infraröd fotografering]]
[[tr:Kızılötesi fotoğraf]]