Photograph
Overview
A photograph is an image
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:...

 created by 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...

 falling on a light-sensitive surface, usually photographic film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...

 or an electronic imager such as a CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

 or a CMOS
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...

 chip. Most photographs are created using a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

, which uses a lens
Photographic lens
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.While in principle a simple convex lens will suffice, in...

 to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating photographs is called 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 word "photograph" was coined in 1839 by Sir John Herschel and is based on the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 φῶς (phos), meaning "light", and γραφή (graphê), meaning "drawing, writing", together meaning "drawing with light".
The first permanent photograph was made in 1822 by a French inventor, Joseph Nicéphore Niépce, building on a discovery by Johann Heinrich Schultz
Johann Heinrich Schultz
Johann Heinrich Schulze or Schultz was a German professor and polymath from Colbitz in the Duchy of Magdeburg.-History:...

 (1724): that a silver and chalk mixture darkens under exposure to light.
Encyclopedia
A photograph is an image
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:...

 created by 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...

 falling on a light-sensitive surface, usually photographic film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...

 or an electronic imager such as a CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

 or a CMOS
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...

 chip. Most photographs are created using a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

, which uses a lens
Photographic lens
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.While in principle a simple convex lens will suffice, in...

 to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating photographs is called 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 word "photograph" was coined in 1839 by Sir John Herschel and is based on the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 φῶς (phos), meaning "light", and γραφή (graphê), meaning "drawing, writing", together meaning "drawing with light".

History

The first permanent photograph was made in 1822 by a French inventor, Joseph Nicéphore Niépce, building on a discovery by Johann Heinrich Schultz
Johann Heinrich Schultz
Johann Heinrich Schulze or Schultz was a German professor and polymath from Colbitz in the Duchy of Magdeburg.-History:...

 (1724): that a silver and chalk mixture darkens under exposure to light. Niépce and Louis Daguerre
Louis Daguerre
Louis-Jacques-Mandé Daguerre was a French artist and physicist, recognized for his invention of the daguerreotype process of photography.- Biography :...

 refined this process. Daguerre discovered that exposing the silver first to iodine vapor, before exposure to light, and then to mercury fumes after the photograph was taken, could form a latent image; bathing the plate in a salt bath then fixes the image. These ideas led to the famous daguerreotype
Daguerreotype
The daguerreotype was the first commercially successful photographic process. The image is a direct positive made in the camera on a silvered copper plate....

.

The daguerreotype had its problems, notably the fragility of the resulting picture, and that it was a positive-only process and thus could not be re-printed. Inventors set about looking for improved processes that would be more practical. Several processes were introduced and used for a short time between Niépce's first image and the introduction of the collodion process
Collodion process
The collodion process is an early photographic process. It was introduced in the 1850s and by the end of that decade it had almost entirely replaced the first practical photographic process, the daguerreotype. During the 1880s the collodion process, in turn, was largely replaced by gelatin dry...

 in 1848. Collodion-based wet-glass plate negatives with prints made on albumen paper
Albumen print
The albumen print, also called albumen silver print, was invented in 1850 by Louis Désiré Blanquart-Evrard, and was the first commercially exploitable method of producing a photographic print on a paper base from a negative...

 remained the preferred photographic method for some time, even after the introduction of the even more practical gelatin process in 1871. Adaptations of the gelatin process have remained the primary black-and-white
Black-and-white
Black-and-white, often abbreviated B/W or B&W, is a term referring to a number of monochrome forms in visual arts.Black-and-white as a description is also something of a misnomer, for in addition to black and white, most of these media included varying shades of gray...

 photographic process to this day, differing primarily in the film material itself, originally glass and then a variety of flexible films
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...

.

Color photography is almost as old as black-and-white, with early experiments dating to John Herschel
John Herschel
Sir John Frederick William Herschel, 1st Baronet KH, FRS ,was an English mathematician, astronomer, chemist, and experimental photographer/inventor, who in some years also did valuable botanical work...

's experiments with Anthotype
Anthotype
An Anthotype is a image created using photosensitive material from plants. This process was originally invented by Sir John Herschel in 1842. An emulsion is made from crushed flower petals or any other light-sensitive plant, fruit or vegetable...

 from 1842, and Lippmann plate
Lippmann plate
Gabriel Lippmann conceived a two-step method to record and reproduce colours, known as:* direct photochromes,* interference photochromes,* Lippmann photochromes,* Photography in natural colours by direct exposure in the camera...

 from 1891. Color photography became much more popular with the introduction of Autochrome Lumière
Autochrome Lumière
The Autochrome Lumière is an early color photography process. Patented in 1903 by the Lumière brothers in France and first marketed in 1907, it was the principal color photography process in use before the advent of subtractive color film in the mid-1930s....

 in 1903, which was replaced by Kodachrome
Kodachrome
Kodachrome is the trademarked brand name of a type of color reversal film that was manufactured by Eastman Kodak from 1935 to 2009.-Background:...

, Ilfochrome
Ilfochrome
Ilfochrome is a dye destruction positive-to-positive photographic process used for the reproduction of slides on photographic paper. The prints are made on a dimensionally stable polyester base, essentially a plastic base opposed to traditional paper base...

 and similar processes. For many years these processes were used almost exclusively for transparencies (in slide projector
Slide projector
A slide projector is an opto-mechanical device to view photographic slides. Slide projectors were common in the 1950s to the 1970s as a form of entertainment; family members and friends would gather to view slide shows...

s and similar devices), but color prints became popular with the introduction of the Chromogenic
Chromogenic
Chromogenic refers to color photographic processes in which a traditional silver image is first formed, and then later replaced with a colored dye image.- Description :...

 negative, which is the most-used system in the C-41 process
C-41 process
C-41 is a chromogenic color print film developing process. C-41, also known as CN-16 by Fuji, CNK-4 by Konica, and AP-70 by AGFA, is the most popular film process in use, with most photofinishing labs devoting at least one machine to this development process....

. The needs of the movie industry have also introduced a host of special-purpose systems, perhaps the best-known being the now rare Technicolor
Technicolor
Technicolor is a color motion picture process invented in 1916 and improved over several decades.It was the second major process, after Britain's Kinemacolor, and the most widely used color process in Hollywood from 1922 to 1952...

.

Types of photographs

Non-digital photographs are produced with a two-step chemical process. In the two-step process the light-sensitive film captures a negative image (colors and lights/darks are inverted). To produce a positive image, the negative is most commonly transferred ('printed
Photographic printing
Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency , or a digital image file projected using an enlarger or digital exposure unit such as a LightJet printer...

') onto photographic paper
Photographic paper
Photographic paper is paper coated with light-sensitive chemicals, used for making photographic prints.Photographic paper is exposed to light in a controlled manner, either by placing a negative in contact with the paper directly to produce a contact print, by using an enlarger in order to create a...

. Printing the negative onto transparent film stock is used to manufacture motion picture films.

Alternatively, the film is processed to invert the negative image, yielding positive transparencies
Transparency (photography)
In photography, a reversal film is a type of photographic film that produces a positive image on a transparent base. Also known as dias or slide. The film is processed to produce transparencies or diapositives instead of negatives and prints...

. Such positive images are usually mounted in frames, called slides. Before recent advances in digital photography, transparencies were widely used by professionals because of their sharpness and accuracy of color rendition. Most photographs published in magazines were taken on color transparency film.

Originally all photographs were monochromatic, or hand-painted in color. Although methods for developing color photos were available as early as 1861, they did not become widely available until the 1940s or 50s, and even so, until the 1960s most photographs were taken in black and white. Since then, Color photography
Color photography
Color photography is photography that uses media capable of representing colors, which are traditionally produced chemically during the photographic processing phase...

 has dominated popular photography, although black and white is still used, being easier to develop than color.

Panoramic format images can be taken with cameras like the Hasselblad
Hasselblad
Victor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....

 Xpan on standard film. Since the 1990s, panoramic photos have been available on the Advanced Photo System
Advanced Photo System
Advanced Photo System is a film format for still photography first produced in 1996. It was marketed by Eastman Kodak under the brand name Advantix, by FujiFilm under the name Nexia, by AgfaPhoto under the name Futura and by Konica as Centuria.- Design :The film is 24 mm wide, and has three...

 film. APS was developed by several of the major film manufacturers to provide a film with different formats and computerized options available, though APS panoramas were created using a mask in panorama-capable cameras, far less desirable than a true panoramic camera, which achieves its effect through a wider film format. APS has become less popular and is being discontinued.

The advent of the microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...

 and digital photography has led to the rise of digital prints
Digital printing
Digital printing refers to methods of printing from a digital based image directly to a variety of media. It usually refers to professional printing where small run jobs from desktop publishing and other digital sources are printed using large format and/or high volume laser or inkjet printers...

. These prints are created from stored graphic formats such as JPEG
JPEG
In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....

, TIFF, and RAW
RAW image format
A camera raw image file contains minimally processed data from the image sensor of either a digital camera, image scanner, or motion picture film scanner. Raw files are so named because they are not yet processed and therefore are not ready to be printed or edited with a bitmap graphics editor...

. The types of printers used include inkjet printer
Inkjet printer
An inkjet printer is a type of computer printer that creates a digital image by propelling droplets of ink onto paper. Inkjet printers are the most commonly used type of printer and range from small inexpensive consumer models to very large professional machines that can cost up to thousands of...

s, dye-sublimation printer
Dye-sublimation printer
A dye-sublimation printer is a computer printer which employs a printing process that uses heat to transfer dye onto medium materials such as a plastic card, paper, or fabric. The sublimation name is applied because the dye transitions between the solid and gas states without going through a...

, laser printer
Laser printer
A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced...

s, and thermal printer
Thermal printer
A thermal printer produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image...

s. Inkjet prints are sometimes given the coined name "Giclée
Giclée
Giclée , is a neologism coined in 1991 by printmaker Jack Duganne for fine art digital prints made on ink-jet printers. The name originally applied to fine art prints created on IRIS printers in a process invented in the late 1980s but has since come to mean any high quality ink-jet print and is...

".

The web
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 has been a popular medium for storing and sharing photos ever since the first photograph was published on the web by Tim Berners-Lee
Tim Berners-Lee
Sir Timothy John "Tim" Berners-Lee, , also known as "TimBL", is a British computer scientist, MIT professor and the inventor of the World Wide Web...

 in 1992 (an image of the CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

 house band Les Horribles Cernettes
Les Horribles Cernettes
Les Horribles Cernettes is an all-female parody pop group, self-labelled "the one and only High Energy Rock Band", founded by employees of CERN which performs at CERN and other HEP related events. Their musical style is often described as doo-wop...

). Today popular sites such as Flickr
Flickr
Flickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...

, Picasa
Picasa
Picasa is an image organizer and image viewer for organizing and editing digital photos, plus an integrated photo-sharing website, originally created by Idealab in 2002 and owned by Google since 2004. "Picasa" is a blend of the name of Spanish painter Pablo Picasso, the phrase mi casa for "my...

 and PhotoBucket
Photobucket
Photobucket is an image hosting, video hosting, slideshow creation and photo sharing website. It was founded in 2003 by Alex Welch and Darren Crystal and received funding from Trinity Ventures. It was acquired by Fox Interactive Media in 2007....

 are used by millions of people to share their pictures.

Paper folders

Ideal photograph storage involves placing each photo in an individual folder constructed from buffered, or acid-free paper
Acid-free paper
Acid-free paper is paper that has a neutral or basic pH . It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin and sulfur free...

. Buffered paper folders are especially recommended in cases when a photograph was previously mounted onto poor quality material or using an adhesive
Adhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

 that will lead to even more acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

 creation. Store photographs measuring 8x10 inches or smaller vertically along the longer edge of the photo in the buffered paper folder, within a larger archival box, and label each folder with relevant information to identify it. The rigid nature of the folder protects the photo from slumping or creasing, as long as the box is not packed too tightly or under filled. Folder larger photos or brittle photos stacked flat within archival boxes with other materials of comparable size.

Polyester enclosures

The most stable of plastics used in photo preservation, polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...

, does not generate any harmful chemical elements, but nor does it have any capability to absorb acids generated by the photograph itself. Polyester sleeves and encapsulation have been praised for their ability to protect the photograph from humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 and environmental pollution, slowing the reaction between the item and the atmosphere. This is true, however the polyester just as frequently traps these elements next to the material it is intended to protect. This is especially risky in a storage environment that experiences drastic fluctuations in humidity or temperature, leading to ferrotyping, or sticking of the photograph to the plastic. Photographs sleeved or encapsulated in polyester cannot be stored vertically in boxes because they will slide down next to each other within the box, bending and folding, nor can the archivist
Archivist
An archivist is a professional who assesses, collects, organizes, preserves, maintains control over, and provides access to information determined to have long-term value. The information maintained by an archivist can be any form of media...

 write directly onto the polyester to identify the photograph. Therefore, it is necessary to either stack polyester protected photographs horizontally within a box, or bind them in a three ring binder. Stacking the photos horizontally within a flat box will greatly reduce ease of access, and binders leave three sides of the photo exposed to the effects of light and do not support the photograph evenly on both sides, leading to slumping and bending within the binder. The plastic used for enclosures has been manufactured to be as frictionless as possible to prevent scratching photos during insertion to the sleeves. Unfortunately, the slippery nature of the enclosure generates a build-up of static electricity
Static electricity
Static electricity refers to the build-up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static electricity can be contrasted with current electricity, which can be delivered...

, which attracts dust
Dust
Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...

 and lint particles. The static can attract the dust to the inside of the sleeve, as well, where it can scratch the photograph. Likewise, these components that aid in insertion of the photo, referred to as slip agents, can break down and transfer from the plastic to the photograph, where they deposit as an oily film, attracting further lint and dust. At this time, there is no test to evaluate the long-term effects of these components on photographs. In addition, the plastic sleeves can develop kinks or creases in the surface, which will scratch away at the emulsion
Emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

 during handling.

Handling and care

It is best to leave photographs lying flat on the table when viewing them. Do not pick it up from a corner, or even from two sides and hold it at eye level. Every time the photograph bends, even a little, this can break down the emulsion
Emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

. The very nature of enclosing a photograph in plastic encourages users to pick it up; users tend to handle plastic enclosed photographs less gently than non-enclosed photographs, simply because they feel the plastic enclosure makes the photo impervious to all mishandling. As long as a photo is in its folder, there is no need to touch it; simply remove the folder from the box, lay it flat on the table, and open the folder. If for some reason the researcher or archivist
Archivist
An archivist is a professional who assesses, collects, organizes, preserves, maintains control over, and provides access to information determined to have long-term value. The information maintained by an archivist can be any form of media...

 does need to handle the actual photo, perhaps to examine the verso for writing, he or she can use gloves if there appears to be a risk from oils or dirt on the hands.

Myths and beliefs

Since daguerreotype
Daguerreotype
The daguerreotype was the first commercially successful photographic process. The image is a direct positive made in the camera on a silvered copper plate....

s were rendered on a mirrored surface, many spiritualists also became practitioners of the new art form. Spiritualists would claim that the human image on the mirrored surface was akin to looking into one's soul. The spiritualists also believed that it would open their souls and let demons in. Aborigines believed that taking one's picture took part of one's soul away.

See also aniconism
Aniconism
Aniconism is the practice or belief in avoiding or shunning images of divine beings, prophets or other respected religious figures, or in different manifestations, any human beings or living creatures. The term aniconic may be used to describe the absence of graphic representations in a particular...

.

Legal issues

Laws on child pornography
Child pornography
Child pornography refers to images or films and, in some cases, writings depicting sexually explicit activities involving a child...

, extreme pornography
Extreme pornography
Section 63 of the Criminal Justice and Immigration Act 2008 is a piece of legislation in the United Kingdom that criminalises possession of what it refers to as "extreme pornographic images". The law was enacted from 26 January 2009...

, etc. often restrict photographs and films even more than the depicted acts: photographs and films of legal acts may be illegal.

See also

  • Archival science
    Archival science
    Archival science is the theory and study of storing, cataloguing, and retrieving documents and items. Archival science evolved from mankind's need to classify the world around them...

  • Digital photography
    Digital photography
    Digital photography is a form of photography that uses an array of light sensitive sensors to capture the image focused by the lens, as opposed to an exposure on light sensitive film...

  • Largest photographs in the world
    Largest photographs in the world
    Most of the photographs that are claimed to be the largest are stitched from smaller images. The Legacy Project photograph made in Irvine, California is an exception to this in that it was made as a single exposure on a seamless piece of sensitized fabric using a building as a huge...

  • Photo slideshow
  • Photograph stability
    Photograph stability
    Photograph stability refers the ability of a photographic print or photographic film to remain visibly unchanged over periods of time. Different photographic processes yield varying degrees of stability.-Silver halide:...

  • Photographic printing
    Photographic printing
    Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency , or a digital image file projected using an enlarger or digital exposure unit such as a LightJet printer...

  • Pseudo-photograph
    Pseudo-photograph
    A pseudo-photograph is "an image, whether made by computer-graphics or otherwise howsoever, which appears to be a photograph".Although the term pseudo-photograph can be applied regardless of what it depicts, in law its meaning is especially relevant regarding child pornography.In the UK, the...

  • Director of Photography
  • View from the Window at Le Gras
    View from the Window at Le Gras
    View from the Window at Le Gras was the first successful permanent photograph, created by Nicéphore Niépce in 1826 at Saint-Loup-de-Varennes....

  • Hand-coloring of photographs
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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