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LIGHTS

Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength. The three basic dimensions of light (i.e., all electromagnetic radiation) are:Intensity (or brilliance or amplitude), which is related to the human perception of brightness of the light, Frequency (or wavelength), perceived by humans as the color of the light, and Polarization (or angle of vibration), which is not perceptible by humans under ordinary circumstances. Due to wave-particle duality, light simultaneously exhibits properties of both waves and particles. The precise nature of light is one of the key questions of modern physics.

COLOR TEMPERATURE

"White light" is commonly described by its color temperature. A traditional incandescent light source's color temperature is determined by comparing its hue with a theoretical, heated black-body radiator. The lamp's color temperature is the temperature in kelvin at which the heated black-body radiator matches the hue of the lamp.

FLASH

In photography, a flash is a device that produces an instantaneous flash of light (typically around 1/1000 of a second) to help illuminate a scene. While flashes can be used for a variety of reasons (e.g. capturing quickly moving subjects) they are mostly used to illuminate scenes that do not have enough available light to adequately expose the photograph. The term flash can either refer to the flash of light itself, or as a colloquialism for the electronic flash unit which discharges the flash of light. The vast majority of flash units today are electronic, having evolved from single-use flash-bulbs and inflammable powders.

In lower-end commercial photography, flash units are commonly built directly into the camera, while higher-end cameras allows separate flash units to be mounted via a standardized accessory mount bracket. In professional studio photography, flashes often take the form of large, standalone units, or studio strobes, that are powered by special battery packs and synchronized with the camera from either a flash synchronization cable, radio transmitter, or are light-triggered, meaning that only one flash unit needs to be synchronized with the camera, which in turn triggers the other units.

Types of flashes

The earliest flashes consisted of a wad of magnesium powder that was ignited by hand. Later, magnesium filaments were contained in flash bulbs, and electrically ignited by a contact in the camera shutter; such a bulb could only be used once, and was too hot to handle immediately after use, but the confinement of what would otherwise have amounted to a small explosion was an important advance.

For the Kodak Instamatic camera, flash cubes of 4 bulbs were introduced, that allowed taking 4 images in a row as the cube automatically rotated 90 degrees to a fresh bulb upon firing. The later Magicube was noteworthy in that each bulb was set off by a plastic pin striking a pyrotechnic element in the flash, so that a battery was not required.

Today's flash units are often electronic xenon flash lamps. An electronic flash contains a tube filled with xenon gas, where electricity of high voltage is discharged to generate an electrical arc that emits a short flash of light. (A typical duration of the light impulse is 1/1000 second.) As of 2003, the majority of cameras targeted for consumer use have an electronic flash unit built in.

Another type of flash unit are microflashes, which are special, high-voltage flash units designed to discharge a flash of light with an exceptionally quick, sub-microsecond duration. These are commonly used by scientists or engineers for examining extremely fast moving objects or reactions, famous for producing images of bullets tearing through objects like lightbulbs or balloons (see Harold Eugene Edgerton).

DARK ROOM

A darkroom is a given space, usually a separate area in a building or a vehicle, that is made dark so as to allow photographers to use light-sensitive materials to develop photographs and film.

The heart of every darkroom is the enlarger -- an optical apparatus that projects the image on a negative to a base. On the base, a sheet of photographic paper, typically either Resin-coated or fibre-based paper, is exposed. It is during this initial exposure that the photo can be modified, mostly by burning(giving more light to specific parts of an image by exposing it while blocking light to the rest) and/or dodging (reducing light to a specific part of an image by blocking light to it). The paper is then developed, rinsed or put into a stop bath, "fixed", then rinsed again and dried. Some darkrooms also have special print washers used to most thoroughly clean the paper.

The darkroom does not have to be completely dark when making black and white prints. Red light or low-intensity orange or yellow light, known as safelights, make it possible to see when making prints without exposing the photographic paper. Color film, on the other hand, must be kept in complete darkness until the prints are properly fixed.

Depending on personal preference, a darkroom may have a "paper-safe", which is a light-proof box to store photographic paper not in use as opposed to the light-proof bags that the paper comes packaged in, and a changing bag, which is a small bag with arm holes specially designed to be completely light proof and used to prepare film prior to developing. The key advantage of using a changing bag is that items used while loading or handling film are less likely to fall or be misplaced as they are enclosed in a small area.

PHOTO JOURNALISM

Photojournalism is a particular form of journalism (the collecting, editing, and presenting of news material for publication or broadcast) that creates images in order to tell a news story. It is now usually understood to refer only to still images, and in some cases to video used in broadcast journalism. Photojournalism is distinguished from other close branches of photography (such as documentary photography, street photography or celebrity photography) by the qualities of:

Timeliness — the images have meaning in the context of a published chronological record of events. Objectivity — the situation implied by the images is a fair and accurate representation of the events they depict. Narrative — the images combine with other news elements, to inform and give insight to the viewer or reader. Photojournalists must make decisions instantly and carry photographic equipment under the same circumstances as those involved in the subject (fire, war, rioting)—often while being exposed to the same risks.

Photojournalism as a descriptive term often implies the use of a certain bluntness of style or approach to image-making. A wedding photographer would not typically be described as a 'photojournalist', even though they cover a timely event and their images may be published in the press.

DIGITAL PHOTOGRAPHY

Traditional photography was a considerable burden for photographers working at remote locations (such as press correspondents) without access to processing facilities. With increased competition from television, there was pressure to deliver their images to newspapers with greater speed. Photo-journalists at remote locations would carry a miniature photo lab with them, and some means of transmitting their images down the telephone line. In 1981, Sony unveiled the first consumer camera to use a CCD for imaging, and which required no film -- the Sony Mavica. While the Mavica did save images to disk, the images themselves were displayed on television, and therefore the camera could not be considered fully digital. In 1990, Kodak unveiled the DCS 100, the first commercially available digital camera. Its cost precluded any use other than photojournalism and professional applications, but commercial digital photography was born.

Digital photography uses an electronic sensor such as a charge-coupled device to record the image as a piece of electronic data rather than as chemical changes on film. Some other devices, such as cell phones, now include digital photography features.

In 10 years, digital cameras have become widespread consumer products. Digital cameras now outsell film cameras, and many include features not found in film cameras such as the ability to shoot video and record audio.

Kodak announced in January 2004 that it would no longer produce reloadable 35-millimeter cameras after the end of that year. This was interpreted as a sign of the end of film photography. However, Kodak was at that time a minor actor on the reloadable film cameras market. The price of 35mm and APS compact cameras have dropped, probably due to direct competition from digital and the resulting growth of the offer of second-hand film cameras. However, "wet" photography may endure, as dedicated amateurs and skilled artists often prefer the use of traditional and familiar materials and techniques.

COMMERCIAL PHOTOGRAPHY

The commercial photographic world is traditionally broken down to:

Advertising photography: photographs made to illustrate a service or product. These images are generally done with an advertising agency, design firm or with an in-house corporate design team. Editorial photography: photographs made to illustrate a story or idea within the context of a magazine. These are usually assigned by the magazine. Photojournalism: this can be considered a subset of editorial photography. Photographs made in this context are accepted as a truthful documentation of a news story. Portrait and wedding photography: photographs made and sold directly to the end user of the images. Fine art photography: photographs made to fulfill a vision, and reproduced to be sold directly to the end user. The market for photographic services demonstrates the aphorism "one picture is worth a thousand words," which has an interesting basis in the history of photography. Magazines and newspapers, companies putting up Web sites, advertising agencies and other groups pay for photography.

Many people take photographs for self-fulfillment or for commercial purposes. Organizations with a budget and a need for photography have several options: they can assign a member of the organization, hire someone, run a public competition, or obtain rights to stock photographs.

DEPTH OF FIELD

The shortest distance an object can be from the film, while still being within acceptable focus is called the hyperfocal distance, and the distance from the hyperfocal distance to the farthest point at which an object is still in focus is the depth of field. Depth of field is controlled primarily by the f/stop; a large aperture will give a lot of blur in the background because light from a point object not in focus will be incident at more angles at the aperture, thus a larger area over the film. Bokeh refers to the quality of the blur in the areas that are not in focus.

FASHION PHOTOGRAPHY

Fashion photography is a specific type of photography devoted to displaying clothes and other fashion items. However, fashion photography had developed its own aesthetic, in which the clothes and fashions (to which they are explicitly devoted) often take a back seat to exotic locations or even story lines (see Eugenio Recuenco). Fashion photography is most often conducted for advertisements or fashion magazines.

WAR PHOTOGRAPHY

War photography is the powerful and often dangerous art of taking pictures of armed conflict and war-torn areas. Photographers who attempt to participate in this genre may find themselves placed in harm's way, and are sometimes killed trying to get their pictures to the outside world. In the Second Persian Gulf War, several photographers were captured and executed by terrorists or shot by armed insurgents. journalists and photographers are generally protected by international conventions of armed warfare, but history has shown that many factions are more then willing to kill them, sometimes to prove how much they hate their opponents and other times to prevent the truth from getting out. War photography has gotten more dangerous in recent years as some terrorists will single out journalists and photographers for targets as easy ways to show proof of their dedication to their cause.

As it is perhaps the most dangerous type of photography, most war photographers are young or energetic, often both, eager to see humanity at its worst and best, the terrors of war mingled with selfless acts of sacrifice. The work that they do and the images they show can be the most powerful and riveting art, as it will uncover the lies of politicians and generals and replace it with the truth. A leader can say that there is no genocide occurring in his country, but a single picture will say otherwise. War photography is an important field as rallying cries of political groups and some of the most powerful emotional images we have are found from glimpses of a battlefield.

FILM DEVELOPEMENT

A piece of photographic film that has been exposed to light in a controlled manner must be developed before it can be used. Development does three things: it transforms the latent image into a visible image that can be seen, it makes the visible image permanent and resistant to deterioration with time, and it renders the film insensitive to light. Photographic paper is developed in a similar manner.

(This article does not apply to Polaroid film, which uses a self-contained developing process.)

The steps to black and white negative film developing are:

The film is removed from the camera and wound onto a reel in complete darkness (usually inside a darkroom or a lightproof bag with arm holes). The reel holds the film in a spiral shape, with space between each successive loop so the chemicals may flow freely across the film's surfaces. The reel is placed in a specially designed light-proof tank. The film is then treated with a series of chemicals: (CONTD:BELOW)

CHEMICALS USED FOR DEVELOPEMENT OF FILM

The first of these is developer, which makes the latent image visible. The second chemical is a stop bath, which stops the action of developer. (Sometimes plain water is used for this step.) It also helps to clean the developer residue off of the film to prevent contaminating the fixer. The third chemical is called fixer. It makes the image permanent and light-resistant. Fixer itself is slightly corrosive, so the film must be washed. Sometimes, it is then placed in a bath of a hypo clearing agent (and sometimes another material, such as selenium). It is then treated with a solution to prevent the appearance of hard-water stains, dried, and cut into strips of a convenient length. In color negative processes the silver halide crystals present in the emulsion need to be removed. This is called bleaching. Bleaching may be done as an additional step or the bleaching agent, usually potassium ferricyanide, may be formulated in with the fixer. Bleaching may be skipped intentionally to create an optical effect on the film called Bleach bypass.

SAFE LIGHT

Safelight is light used in a photographic darkroom and is designed to filter out that part of the light spectrum to which the material in use is sensitive. A safelight usually consists of an ordinary lightbulb in a housing with a coloured filter, but it is possible to buy special bulbs and fluorescent tubes which are coated with a filter directly on the glass.

Initially, monochrome photographic film was sensitive to blue and green light and could be handled under a deep red light. This material was called Orthochromatic film meaning that it theoretically correctly reproduced any colour as a shade of grey. However since it was designed to be handled in red light it actually meant that any red objects were rendered as black. Manufacturers then developed Panchromatic film but since this was sensitive to red light it has to be handled in either total darkness or in some instances a dark brown or violet light can be used. In either case these safelights are sodim as to be almost useless.

Until the middle of the 20th century, monochrome photographic paper was sensitive to blue and green light and required a deep red safelight. Photographic paper has been sensitive to just blue light for a great many years now, enabling yellow safelights to be used which provide much more light for the photographer to work in. Despite this, darkroom scenes in movies invariably show the use of a red light.

DODGING

Dodging is a term used in the photography industry. Dodging is a technique used during the printing process to lighten a specific portion of the print. For example, a photograph may contain unwanted shadows. Dodging can lighten the shadows which can allow more detail in the shadow region to show.

Unlike the burning-in process, dodging is done during the initial exposure period. A card or other opaque object is held between the enlarger lens and the photographic paper in such a way as to block light from that portion of the scene to be lightened. The dodged area receives less light and, therefore, less exposure. Less exposure on photographic paper results in a lighter image.

Ansel Adams elevated burning and dodging to an art form. Many of his famous prints were manipulated in the darkroom with these two techniques. Adams wrote a comprehensive book on this very topic called The Print.