Ultraviolet photography
Encyclopedia
Ultraviolet photography is a photographic process of recording image
s by using light
from the ultraviolet
(UV) spectrum
only.
Light which is visible to the human eye
covers the spectral region from about 400 to 750 nanometers. This is the radiation
spectrum used in normal photography
. The band of radiation that extends from about 1 nm to 400 nm is known as ultraviolet radiation. UV spectrographers divide this range into three bands:
Only near UV is of interest for UV photography, for several reasons. Ordinary air is opaque to wavelengths below about 200 nm, and lens glass is opaque below about 180 nm. UV photographers subdivide the near UV into:
(These terms should not be confused with the parts of the radio spectrum with similar names.)
There are two ways to use UV radiation to take photograph
s - reflected ultraviolet and ultraviolet fluorescence
photography. Reflected ultraviolet photography finds practical use in medicine
, dermatology
, criminology
and theatrical
applications. Sunlight is the most available free UV radiation source, but the quality and quantity of the radiation depends on atmospheric
conditions. A bright and dry day is much richer in UV radiation and is preferable to a cloudy or rainy day.
Another suitable source is electronic flash which can be used efficiently in combination with an aluminium
reflector. Some flash units have a special UV absorbing glass over the flash tube, which must be removed before the exposure. It also helps to partly (90%) remove the gold coating of some flash tubes which otherwise suppresses UV.
Special UV lamps known as "black light
" fluorescence tubes are used for long wave ultraviolet photography. Most modern UV sources are based on a mercury
arc sealed in a glass tube. By coating the tube internally with a suitable phosphor
, it becomes an effective long wave UV source.
s, usually from about 350 nm and below. Only special developed lenses made of quartz (fused silica) or quartz and fluorite can be used. Using these lenses allow the camera to reach the range 180..200 nm. Lenses based purely on quartz show a distinct focus shift between visible and UV light, whereas the later developed fluorite/quartz lenses are fully color corrected without focus shift. Examples of the latter type are the Nikon UV Nikkor 105 mm, the Hasselblad (Zeiss) UV Sonnar 105 mm and the Asahi Pentax Ultra Achromatic Takumar 85 mm.
Photography based on (visible
) fluorescence induced by UV radiation has better results in archaeological
photography. The same ultraviolet light sources as in reflected UV photography, except that a glass
filter is used to absorb all the visible light and allow only the desired ultraviolet to pass. These filters are sometimes incorporated in the source tube itself, but most of the time are separate elements. These filter glasses usually allow a small amount of violet
visible light. This should not be confused with UV light, which is invisible to the human eye. The same kind of filters are made for flash tubes also, by BALCAR and other lighting companies.
This filter is called an "exciter" filter and it allows only the radiation needed to excite fluorescence. A second filter must be placed in front of the camera lens, to exclude residual ultraviolet and allow the resulting fluorescence excited in the sample by the UV source. This filter is called the "barrier" filter. Kodak Wratten 2A - 2B is effective, as is the Baader UV/IR Cut filter. Using a 2E filter gives better results in some situations. The same filters are also made by other companies with the same codes.
The shooting must take place in a darkened room, with a black background. The photographer should also wear dark-colored clothes for better results. (Many light-colored fabrics also fluoresce under UV.)
Suitable digital cameras for reflected UV photography have been reported to be the (unmodified) Nikon D70, D40 and Fuji Film S5 cameras, but others might be suitable after having their internal filter removed. If using a modern digital camera (DSLR), it would be advisable to additionally use an IR blocking, yet UV transmissive filter to avoid IR leakage. Schott BG-38 and BG-40 are suitable for this purpose.
The Fujifilm FinePix IS PRO
digital SLR camera is purpose-designed for ultraviolet (and infrared) photography, with a frequency response rated from 1000-380nm, although it also responds to somewhat longer and shorter wavelengths. Silicon (from which the sensor
is made) can respond to wavelengths between 1100-190nm.
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
s by using light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
from the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
(UV) spectrum
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
only.
Overview
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
covers the spectral region from about 400 to 750 nanometers. This is the radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
spectrum used in normal photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
. The band of radiation that extends from about 1 nm to 400 nm is known as ultraviolet radiation. UV spectrographers divide this range into three bands:
- near UV (380–200 nm wavelength; abbrev. NUV)
- far UV (or vacuum UV) (200–10 nm; abbrev. FUV or VUV)
- extreme UV (1–31 nm; abbrev. EUV or XUV).
Only near UV is of interest for UV photography, for several reasons. Ordinary air is opaque to wavelengths below about 200 nm, and lens glass is opaque below about 180 nm. UV photographers subdivide the near UV into:
- Long wave UV that extends from 320 to 400 nm, also called UV-A,
- Medium wave UV that extends from 280 to 320 nm, also called UV-B,
- Short wave UV that extends from 200 to 280 nm, also called UV-C.
(These terms should not be confused with the parts of the radio spectrum with similar names.)
There are two ways to use UV radiation to take photograph
Photograph
A photograph is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic imager such as a CCD or a CMOS chip. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of...
s - reflected ultraviolet and ultraviolet fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
photography. Reflected ultraviolet photography finds practical use in medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, dermatology
Dermatology
Dermatology is the branch of medicine dealing with the skin and its diseases, a unique specialty with both medical and surgical aspects. A dermatologist takes care of diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails....
, criminology
Criminology
Criminology is the scientific study of the nature, extent, causes, and control of criminal behavior in both the individual and in society...
and theatrical
Theatre
Theatre is a collaborative form of fine art that uses live performers to present the experience of a real or imagined event before a live audience in a specific place. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music or dance...
applications. Sunlight is the most available free UV radiation source, but the quality and quantity of the radiation depends on atmospheric
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
conditions. A bright and dry day is much richer in UV radiation and is preferable to a cloudy or rainy day.
Another suitable source is electronic flash which can be used efficiently in combination with an aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
reflector. Some flash units have a special UV absorbing glass over the flash tube, which must be removed before the exposure. It also helps to partly (90%) remove the gold coating of some flash tubes which otherwise suppresses UV.
Special UV lamps known as "black light
Black light
A black light, also referred to as a UV light, ultraviolet light, or Wood's lamp, is a lamp that emits ultraviolet radiation in the long-wave range, and little visible light...
" fluorescence tubes are used for long wave ultraviolet photography. Most modern UV sources are based on a mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
arc sealed in a glass tube. By coating the tube internally with a suitable phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...
, it becomes an effective long wave UV source.
Reflected UV photography
In reflected UV photography the subject is illuminated directly by UV emitting lamps (radiation sources). A UV transmitting, visible light blocking filter is placed on the lens, that allows ultraviolet to pass and absorbs all visible light. Examples of these filters are Kodak Wratten 18A, B+W 403, Hoya U-340, Baader U-Filter and Kenko U-360. These filters are made from special colored glass. Most types of glass will allow long wave UV to pass, but absorb all the other UV wavelengthWavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s, usually from about 350 nm and below. Only special developed lenses made of quartz (fused silica) or quartz and fluorite can be used. Using these lenses allow the camera to reach the range 180..200 nm. Lenses based purely on quartz show a distinct focus shift between visible and UV light, whereas the later developed fluorite/quartz lenses are fully color corrected without focus shift. Examples of the latter type are the Nikon UV Nikkor 105 mm, the Hasselblad (Zeiss) UV Sonnar 105 mm and the Asahi Pentax Ultra Achromatic Takumar 85 mm.
Ultraviolet fluorescence photography
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
) fluorescence induced by UV radiation has better results in archaeological
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...
photography. The same ultraviolet light sources as in reflected UV photography, except that a glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
filter is used to absorb all the visible light and allow only the desired ultraviolet to pass. These filters are sometimes incorporated in the source tube itself, but most of the time are separate elements. These filter glasses usually allow a small amount of violet
Violet (color)
As the name of a color, violet is synonymous with a bluish purple, when the word "purple" is used in the common English language sense of any color between blue and red, not including either blue or red...
visible light. This should not be confused with UV light, which is invisible to the human eye. The same kind of filters are made for flash tubes also, by BALCAR and other lighting companies.
This filter is called an "exciter" filter and it allows only the radiation needed to excite fluorescence. A second filter must be placed in front of the camera lens, to exclude residual ultraviolet and allow the resulting fluorescence excited in the sample by the UV source. This filter is called the "barrier" filter. Kodak Wratten 2A - 2B is effective, as is the Baader UV/IR Cut filter. Using a 2E filter gives better results in some situations. The same filters are also made by other companies with the same codes.
The shooting must take place in a darkened room, with a black background. The photographer should also wear dark-colored clothes for better results. (Many light-colored fabrics also fluoresce under UV.)
Suitable digital cameras for reflected UV photography have been reported to be the (unmodified) Nikon D70, D40 and Fuji Film S5 cameras, but others might be suitable after having their internal filter removed. If using a modern digital camera (DSLR), it would be advisable to additionally use an IR blocking, yet UV transmissive filter to avoid IR leakage. Schott BG-38 and BG-40 are suitable for this purpose.
The Fujifilm FinePix IS PRO
FinePix IS Pro
The FinePix IS Pro is a digital single lens reflex camera introduced by Fujifilm in 2007. It is based on a FinePix S5 Pro, which is in turn based on the Nikon D200. It has a Nikon F lens mount and can use most lenses made for 35 mm Nikon SLR cameras. It replaces the Fujifilm FinePix S3 Pro...
digital SLR camera is purpose-designed for ultraviolet (and infrared) photography, with a frequency response rated from 1000-380nm, although it also responds to somewhat longer and shorter wavelengths. Silicon (from which the sensor
Active pixel sensor
An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...
is made) can respond to wavelengths between 1100-190nm.
See also
- Ultraviolet video
- Infrared photographyInfrared photographyIn infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about...
- Fujifilm FinePix IS PROFinePix IS ProThe FinePix IS Pro is a digital single lens reflex camera introduced by Fujifilm in 2007. It is based on a FinePix S5 Pro, which is in turn based on the Nikon D200. It has a Nikon F lens mount and can use most lenses made for 35 mm Nikon SLR cameras. It replaces the Fujifilm FinePix S3 Pro...
UV- (and IR-) sensitive DSLR camera