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The conservation and restoration of photographs is the study of the physical care and treatment of photographic materials. It covers both efforts undertaken by
photograph conservator A photograph conservator is a professional who examines, documents, researches, and treats photographs, including documenting the structure and condition of art works through written and photographic records, monitoring conditions of works in sto ...
s,
librarian A librarian is a person who professionally works managing information. Librarians' common activities include providing access to information, conducting research, creating and managing information systems, creating, leading, and evaluating educat ...
s,
archivist An archivist is an information professional who assesses, collects, organizes, preserves, maintains control over, and provides access to records and archives determined to have long-term value. The records maintained by an archivist can cons ...
s, and museum
curator A curator (from , meaning 'to take care') is a manager or overseer. When working with cultural organizations, a curator is typically a "collections curator" or an "exhibitions curator", and has multifaceted tasks dependent on the particular ins ...
s who manage photograph collections at various
cultural heritage Cultural heritage is the heritage of tangible and intangible heritage assets of a group or society that is inherited from past generations. Not all heritages of past generations are "heritage"; rather, heritage is a product of selection by socie ...
institutions, as well as steps taken to preserve collections of personal and family photographs. It is an umbrella term that includes both preventative preservation activities such as environmental control and conservation techniques that involve treating individual items. Both preservation and conservation require an in-depth understanding of how photographs are made, and the causes and prevention of deterioration. Conservator-restorers use this knowledge to treat photographic materials, stabilizing them from further deterioration, and sometimes restoring them for aesthetic purposes. While conservation can improve the appearance of a photograph, image quality is not the primary purpose of conservation. Conservators will try to improve the visual appearance of a photograph as much as possible, while also ensuring its long-term survival and adhering the profession's ethical standards. Photograph conservators also play a role in the field of
connoisseur A connoisseur (French language, French Reforms of French orthography, traditional, pre-1835, spelling of , from Middle-French , then meaning 'to be acquainted with' or 'to know somebody/something') is a person who has a great deal of knowledge ...
ship. Their understanding of the physical object and its structure makes them uniquely suited to a technical examination of the photograph, which can reveal clues about how, when, and where it was made. Photograph preservation is distinguished from ''digital'' or ''optical restoration'', which is concerned with creating and editing a digital copy of the original image rather than treating the original photographic material. Photograph preservation does not normally include moving image materials, which by their nature require a very different approach.
Film preservation Film preservation, or film restoration, describes a series of ongoing efforts among film historians, archivists, museums, cinematheques, and non-profit organizations to rescue decaying film stock and preserve the images they contain. In the wide ...
concerns itself with these materials.


Photographic processes

Physical photographs usually consist of three components: the final image material (e.g. silver, platinum, dyes, or pigments), the transparent binder layer (e.g. albumen, collodion, or gelatin) in which the final image material is suspended, and the primary support (e.g. paper, glass, metal, or plastic). These components affect the susceptibility of photos to damage and the preservation and conservation methods required.American Institute for Conservation of Historic and Artistic Works (AIC), ''Caring for Your Treasures'', accessed August 12, 2011, http://www.conservation-us.org/_data/n_0001/resources/live/photographs.pdf. Photograph preservation and conservation are also concerned with the negatives from which most old photographic prints are made. Most negatives are either glass plate or film-based.


Timeline

Source: 1816:
Heliography Heliography is an early photographic process, based on the hardening of bitumen in sunlight. It was invented by Nicéphore Niépce around 1822. Niépce used the process to make the earliest known surviving photograph from nature, '' View from ...

The first person who succeeded in producing a paper negative of the camera image was Joseph Nicephore Niepce. He coated pewter plates with
bitumen Bitumen ( , ) is an immensely viscosity, viscous constituent of petroleum. Depending on its exact composition, it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American Engl ...
(an asphaltic varnish that hardens with exposure to light) and put them in a
Camera Obscura A camera obscura (; ) is the natural phenomenon in which the rays of light passing through a aperture, small hole into a dark space form an image where they strike a surface, resulting in an inverted (upside down) and reversed (left to right) ...
. After exposure to sunlight for a long time, the parts that were exposed to light became hard and the parts that were not could be washed off with
lavender oil Lavender oil is an essential oil obtained by distillation from the flower spikes of certain species of lavender. It is commonly used in aromatherapy, perfumery, and as a flavoring or fragrance in consumer products. A standardized oral ...
. 1837:
Daguerreotype Daguerreotype was the first publicly available photography, photographic process, widely used during the 1840s and 1850s. "Daguerreotype" also refers to an image created through this process. Invented by Louis Daguerre and introduced worldwid ...

The daguerreotype process (named after
Louis Jacques Mande Daguerre Louis-Jacques-Mandé Daguerre ( ; ; 18 November 1787 – 10 July 1851) was a France, French scientist, artist and photographer, recognized for his invention of the eponymous daguerreotype process of photography. He became known as one of th ...
) produces a unique image, as there is no negative created. After coating a copper plate with light-sensitive silver iodide, the plate is exposed to an image for over 20 minutes and then treated with fumes from heated mercury. The longer the exposure to light, the more mercury fumes are adsorbed by the silver iodide. After the plate is washed with salt water, the image appears, reversed. This was the earliest photographic process to gain popularity in America.Debbie Hess Norris, "The Proper Storage and Display of a Photographic Collection", ''The Book and Paper Annual'' 2 (1983), accessed August 12, 2011, http://cool.conservation-us.org/coolaic/sg/bpg/annual/v02/bp02-08.html. It was used until around 1860.Gary Albright and Monique Fischer, ''Types of Photographs'', Preservation Leaflets (Northeast Document Conservation Center), accessed August 12, 2011, http://www.nedcc.org/resources/leaflets/5Photographs/02TypesOfPhotos.php . 1839:
Salt print The salt print was the dominant paper-based photographic process for producing positive prints (from negatives) from 1839 until approximately 1860. The salted paper technique was created in the mid-1830s by English scientist and inventor He ...

This was the dominant form of paper print until Albumen prints were introduced in 1850. Salt prints were made using both paper and glass negatives. 1841:
Calotype Calotype or talbotype is an early photographic process introduced in 1841 by William Henry Fox Talbot, using paper coated with silver iodide. Paper texture effects in calotype photography limit the ability of this early process to record low ...

William Henry Fox Talbot William Henry Fox Talbot (; 11 February 180017 September 1877) was an English scientist, inventor, and photography pioneer who invented the Salt print, salted paper and calotype processes, precursors to photographic processes of the later 19th ...
invented the negative-positive system of photography commonly used today. He first developed the Talbotype, which used silver chloride to sensitize paper. After improving the process by using silver iodide, he renamed it Calotype. The process could produce many positive images, but they were not as sharp because they were printed on fibrous paper rather than glass. 1842:
Cyanotype The cyanotype (from , and , ) is a slow-reacting, photographic printing formulation sensitive to a limited near-ultraviolet and blue light spectrum, the range 300 nm to 400 nm known as UVA radiation. It produces a monochrome, blu ...
(Ferro-plusiate, Blue process)
This process forms blue-colored images through a reaction to iron salts.
John Herschel Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor and experimental photographer who invented the blueprint and did botanical work. ...
studied it in order to reproduce his complicated math formulas and memos. Other processes that fall into this category include Kallitype, Vandyketype, and Platinum printing. 1850:
Albumen print Egg white is the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens, it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms aro ...

This process, introduced by
Louis Désiré Blanquart-Evrard Louis Désiré Blanquart-Evrard (2 August 1802 – 28 April 1872) was a French inventor, photographer and photo publisher. Being a cloth merchant by trade, in the 1840s he developed interest in photography and focused on technical and economical ...
, was the most common kind of print in the latter half of the nineteenth century. Beautiful sepia gradation images were created by using albumen and silver chloride. The surfaces of prints made with this process were glossy because of the egg whites which were layered heavily to prevent the originally thin prints from curling, cracking, or tearing easily. This type of print was especially common for studio portraits and landscape or stereoviews. 1851: Wet collodion process and
Ambrotype The ambrotype, also known as a collodion positive in the UK, is a positive photograph on glass made by a variant of the wet plate collodion process. As a cheaper alternative to the French daguerreotype, ambrotypes came to replace them. Like a ...

Frederick Scott Archer ] Frederick Scott Archer (1813 – 1 May 1857) was an English photographer and sculptor who is best known for having invented the photographic collodion process which preceded the modern photographic film, gelatin emulsion. He was born in either ...
developed the wet collodion processes, which used a thick glass plate unevenly hand-coated with a collodion-based, light-sensitive emulsion. Collodion, which means ‘glue’ in Greek, is nitrocellulose dissolved in ether and ethanol. The
Ambrotype The ambrotype, also known as a collodion positive in the UK, is a positive photograph on glass made by a variant of the wet plate collodion process. As a cheaper alternative to the French daguerreotype, ambrotypes came to replace them. Like a ...
, an adaptation of the wet collodion process, was developed by Archer and Peter W. Fry. It involved placing a dark background behind the glass so that the negative image would look positive, and was popular in America until around 1870. 1855:
Gum printing Gum printing is a way of making photographic reproductions without the use of silver halides. The process uses salts of dichromate in common with a number of other related processes such as sun printing. Gum prints tend to be multi-layered im ...

Orange colored dichromate has photosensitivity when it is mixed with colloids such as gum arabic, albumen, or gelatin. Using that feature,
Alphonse Poitevin Alphonse Louis Poitevin ( Conflans-sur-Anille, 1819 – Conflans-sur-Anille, 1882) was a French chemist, photographer and civil engineer who discovered the light–sensitive properties of bichromated gelatin and invented both the photolithography a ...
invented the gum printing process. It gained in popularity after 1898, and again in 1960s and 1970s because of its unique look. 1858:
Tintype A tintype, also known as a melanotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of metal, colloquially called 'tin' (though not actually tinplate, tin-coated), coated with a dark lacquer or Enamel paint, ...
(also called Ferrotype and Melainotype)
In this photographic process the emulsion was painted directly onto a japanned (varnish finish) iron plate. it was much cheaper and sturdier than the Ambrotype and Daguerreotype. 1861: RGB additive color model
Applied physician
James Clerk Maxwell James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism an ...
made the first color photo by mixing red, green, and blue light. 1871: Gelatin dry plate
Richard L. Maddox discovered that gelatin could be a carrier for silver salts. By 1879, the gelatin dry plate had replaced the collodion wet plate. It was a revolutionary innovation in photography since it needed less light exposure, was usable when dry, meaning photographers no longer needed to pack and carry dangerous liquids, and could be standardized because it could be factory produced. 1873: Platinum printing (Platinotype)
William Willis patented platinum printing in Britain. The process rapidly spread and became a dominant method in Europe and America by 1894 since it had a visibly different color tone compared to albumen and gelatin silver prints. Late 1880s:
Gelatin silver print The gelatin silver print is the most commonly used chemical process in black-and-white photography, and is the fundamental chemical process for modern analog color photography. As such, films and printing papers available for analog photography r ...

This has been the major photograph printing process since the late 1880s up to the present. Prints consist of paper coated with an emulsion of silver halide in gelatin. The surface is generally smooth; under magnification, the print appears to sparkle. 1889:
Kallitype Kallitype is a process for making photographic prints. Patented in 1889 by W. W. J. Nicol (1855-1929), the Kallitype print is an iron-silver process. A chemical process similar to the Van Dyke brown (printing), Van Dyke brown based on the use of a ...

Dr. W. W. J. Nicol invented and refined the Kallitype. Vandyketype, or Single Kalliitype, is the simplest type of Kalltype and creates beautiful brown images. 1889: Film negatives
Cellulose nitrate film was developed by
Eastman Kodak The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated i ...
in 1889 and refined in 1903. It is made of silver gelatin on a cellulose nitrate base. The negatives are flammable and therefore can be dangerous. Nitrate sheet film was used widely though the 1930s, while nitrate roll film was used through the 1950s. The nitrate base was replaced with
cellulose acetate In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and ...
in 1923. By 1937, Cellulose diacetate was used as the base, and beginning in 1947 Cellulose triacetate was used. Polyester film was introduced around 1960.International Federation of Library Associations and Institutions (IFLA) Core Programme Preservation and Conservation, ''Care, Handling and Storage of Photographs: Information Leaflet'', (1992, revised and updated 2002), accessed August 12, 2011, https://www.loc.gov/preservation/resources/care/photolea.html. 1935:
Color photographs Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though co ...

Kodak introduced color film and transparencies in 1935. The first process was called
Kodachrome Kodachrome is the brand name for a color reversal film introduced by Eastman Kodak in 1935. It was one of the first successful color materials and was used for both cinematography and still photography. For many years, Kodachrome was widely used ...
.
Ektachrome Ektachrome is a brand name owned by Kodak for a range of transparency, still and motion picture films previously available in many formats, including 35 mm and sheet sizes to 11 × 14 inch size. Ektachrome has a distinctive look that ...
, introduced in the late 1940s, became equally popular. There are now a variety of color processes that use different materials; most consist of dyes (cyan, magenta, and yellow, each of which have different absorption peaks) suspended in a gelatin layer.


Photograph stability

Photograph stability refers to the ability of prints and
film A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, sinc ...
to remain visibly unchanged over periods of time. Different photographic processes yield varying degrees of stability. In addition, different materials may have dark-storage stability which differs from their stability in light. ;Kodachrome: An extreme case with slides was stability under the intense light of projection. When stored in darkness, Kodachrome's long-term stability under suitable conditions is superior to other types of color film. Images on Kodachrome slides over fifty years old retain accurate color and density. Kodachrome film stored in darkness is largely responsible for excellent color footage of World War II, for example. It has been calculated that the yellow dye in Kodachrome, the least stable, would suffer a 20% loss of dye in 185 years. This is because developed Kodachrome does not retain unused color couplers. However, Kodachrome's color stability under bright light, especially during
projection Projection or projections may refer to: Physics * Projection (physics), the action/process of light, heat, or sound reflecting from a surface to another in a different direction * The display of images by a projector Optics, graphics, and carto ...
, is inferior to substantive slide films. Kodachrome's fade time under projection is about one hour, compared to Fujichrome's two and a half hours. Thus, old Kodachrome slides should be exposed to light only when copying to another medium. ;Silver halide:
Black-and-white Black-and-white (B&W or B/W) images combine black and white to produce a range of achromatic brightnesses of grey. It is also known as greyscale in technical settings. Media The history of various visual media began with black and white, ...
negatives and prints made by the
silver halide A silver halide (or silver salt) is one of the chemical compounds that can form between the Chemical element, element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine wit ...
process are stable so long as the photographic substrate is stable. Some papers may yellow with age, or the
gelatin Gelatin or gelatine () is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolyzed collagen, coll ...
matrix may yellow and crack with age. If not developed properly, small amounts of
silver halide A silver halide (or silver salt) is one of the chemical compounds that can form between the Chemical element, element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine wit ...
remaining in the gelatin will darken when exposed to light. In some prints, the black silver oxide is reduced to metallic silver with time, and the image takes on a metallic sheen as the dark areas reflect light instead of absorbing it.
Silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...
can also react with
sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
in the air and form
silver sulfide Silver sulfide is an inorganic compound with the formula . A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver ob ...
. A correctly processed and stored silver print or negative probably has the greatest stability of any photographic medium, as attested by the wealth of surviving historical black-and-white photographs. ;Chromogenic:
Chromogenic In chemistry, the term chromogen refers to a colourless (or faintly coloured) chemical compound that can be converted by chemical reaction into a compound which can be described as "coloured" (a chromophore). There is no universally agreed definiti ...
dye color processes include Type "R" and process RA-4 (also known as "type C prints"), process C-41 color negatives. and process E-6 color reversal (
Ektachrome Ektachrome is a brand name owned by Kodak for a range of transparency, still and motion picture films previously available in many formats, including 35 mm and sheet sizes to 11 × 14 inch size. Ektachrome has a distinctive look that ...
) film. Chromogenic processes yield organic dyes that are less stable than silver, and can also leave unreacted dye couplers behind during developing. Both factors may lead to color changes over time. The three dyes, cyan, magenta, and yellow, which make up the print may fade at different rates, causing a color shift in the print. Modern chromogenic papers such as
Kodak The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated i ...
Endura have achieved excellent stability, however, and are rated for 100 years in home display. ;Dye destruction:
Dye destruction Dye destruction or dye bleach is a photographic printing process, in which dyes embedded in the paper are bleached (destroyed) in processing. Because the dyes are fully formed in the paper prior to processing, they may be formulated with few constr ...
prints are the most archival color prints, at least among the wet chemical processes, and arguably among all processes. The most well-known kind of
dye destruction Dye destruction or dye bleach is a photographic printing process, in which dyes embedded in the paper are bleached (destroyed) in processing. Because the dyes are fully formed in the paper prior to processing, they may be formulated with few constr ...
print is the
Cibachrome Ilfochrome (also commonly known as Cibachrome) is a dye destruction positive-to-positive photographic process used for the reproduction of film transparencies on photographic paper. The prints are made on a dimensionally stable polyester base as o ...
, now known as
Ilfochrome Ilfochrome (also commonly known as Cibachrome) is a dye destruction positive-to-positive photographic process used for the reproduction of film transparencies on photographic paper. The prints are made on a dimensionally stable polyester base as ...
. ;Ink jet: Some
ink jet Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper or plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive ...
prints are now considered to have excellent stability, while others are not. Ink jet prints using
dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...
-
pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...
mixtures are now common in photography, and often claim stability on par with
chromogenic In chemistry, the term chromogen refers to a colourless (or faintly coloured) chemical compound that can be converted by chemical reaction into a compound which can be described as "coloured" (a chromophore). There is no universally agreed definiti ...
prints. However, these claims are based on
accelerated aging Accelerated aging is testing that uses aggravated conditions of heat, humidity, oxygen, sunlight, vibration, etc. to speed up the normal aging processes of items. It is used to help determine the long-term effects of expected levels of stress wi ...
studies rather than historical experience, because the technology is still relatively young.


Types and causes of deterioration

There are two main types of deterioration found in photographic materials. Chemical deterioration occurs when the chemicals in the photograph or negative undergo reactions (either through contact with outside catalysts, or because the chemicals are inherently unstable) that damage the material. Physical or structural deterioration occurs when chemical reactions are not involved, and include abrasion and tearing. Both types of deterioration are caused by three main factors: environmental storage conditions, inappropriate storage enclosures and repair attempts, and human use and handling. Chemical damage can also be caused by improper chemical processing. Different types of photographic materials are particularly susceptible to different types and causes of deterioration.


Environmental factors

* Temperature and humidity interact with one another and cause chemical and physical deterioration. High temperature and
relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...
, along with pollution, can cause fading and discoloration of silver images and color dyes. Higher temperatures cause faster deterioration: the rate of deterioration is approximately doubled with every temperature increase of 10 °C. Fluctuations in temperature and relative humidity are particularly damaging, as they also speed up chemical deterioration and can cause structural damage such as cracked emulsions and warped support layers.Gary Albright and Monique Fischer, ''Care of Photographs'', Preservation Leaflets (Northeast Document Conservation Center), accessed August 12, 2011, . :*Too-high relative humidity can cause fading, discoloration and silver mirroring, and can cause binders to soften and become sticky, making photographs susceptible to physical damage. It can also cause photographs to adhere to frames and other enclosures. :*Too-low relative humidity can cause physical damage including desiccation, embrittlement, and curling. * Pollution can include oxidant and acidic / sulfiding gases that cause chemical deterioration, as well as dust and particulates that can cause abrasion.Ross, "Silver-Based Photographic Prints and Negatives," 40. Sources of indoor pollution that affect photographs include paint fumes, plywood, cardboard, and cleaning supplies. * Exposure to light causes embrittlement, fading, and yellowing. The damage is cumulative and usually irreversible. UV light (including from sunlight and fluorescent light) and visible light in the blue part of the spectrum are especially harmful to photographs, but all forms of light, including incandescent and tungsten, are damaging. * Mold growth is fostered by high temperatures and humidity as well as dust particles. They cause damage to the surface of photographs and help break down binder layers. * The presence of insects and rodents is also fostered by high temperatures and humidity. They eat paper fiber, albumen, and gelatin binders, leaving chew marks and droppings. Species likely to cause problems include
cockroach Cockroaches (or roaches) are insects belonging to the Order (biology), order Blattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known Pest (organism), pests. Modern cockro ...
es and
silverfish The silverfish (''Lepisma saccharinum'') is a species of small, primitive, wingless insect in the order Zygentoma (formerly Thysanura). Its common name derives from the insect's silvery light grey colour, combined with the fish-like appearanc ...
.


Other factors

;Inappropriate storage containers and repair attempts: Cabinets made of inferior materials can give off harmful gases, while other reactive materials such as acidic paper sleeves, rubber bands, paper clips,
pressure sensitive tape Pressure-sensitive tape or pressure-sensitive adhesive tape (PSA tape) is an adhesive tape that sticks when pressure is applied without the need for a solvent (such as water) or heat for activation. It is also known in various countries as self- ...
, and glues and adhesives commonly used for storage and repairs in the past can also cause chemical deterioration. Storing items too loosely, too tightly, or in enclosures that do not provide adequate physical protection can all cause physical damage such as curling and breakage. ;Handling and use: Human handling, including by researchers and staff, can also cause both chemical and physical deterioration. Oils, dirt, lotions, and perspiration transmitted through fingerprints can destroy emulsion and cause bleaching, staining, and silver mirroring.Hamill, ''Preserving Your Family Photographs'', 2. Physical damage caused by human handling includes abrasion, scratches, tears, breakage, and cracks. ;Improper chemical processing: Chemical processing, including use of exhausted fixer, insufficient length of fixing, and residual fixer left behind by inadequate washing can cause fading and discoloration. Heat, humidity, and light can accelerate such damage. Adherence to ISO standards at the time of processing can help avoid this type of deterioration.


Examples of threats to specific photographic materials

Glass plate negatives and ambrotypes are prone to breakage. Deterioration of film negatives, regardless of type, is humidity and temperature dependent. Nitrate film will first fade, then become brittle and sticky. It will then soften, adhere to paper enclosures, and produce an odor. Finally, it will disintegrate into a brown, acrid powder.Messier, "Preserving Your Collection of Film-Based Negatives". Because of its flammability, it must be handled with particular care. Cellulose aetate, diacetate, and triacetate film produce acetic acid, which smells like vinegar. The deterioration process is therefore known as "
vinegar syndrome Vinegar Syndrome is an American home video distribution company which specializes in "protecting and preserving genre films". The company was founded in 2012 in Bridgeport, Connecticut by Joe Rubin and Ryan Emerson, who created it to restore ...
". The negatives become very brittle and, in diacetate and triacetate film, the base shrinks, causing grooves ("channeling"). In addition to fading, silver-based images are prone to silver mirroring, which presents as a bluish metallic sheen on the surface of the photograph or negative and is caused by oxidation, which causes the silver to migrate to the surface of the emulsion. Color photographs are an inherently unstable medium, and are more susceptible to light and fading than black and white photographic processes. They are composed of various dyes, all of which eventually fade, albeit at different rates (causing discoloration along with fading).Norman, "Photographic Collections Management". Many color photographic processes are also susceptible to fading even in the dark (known as "dark-fading"). There is little that can be done to restore faded images, and even under ideal conditions, most color photographs will not survive undamaged for more than 50 years.


Preservation strategies


Temperature and relative humidity control

Maintenance of a proper environment such as control of temperature and relative humidity (RH; a measure of how saturated the air is with moisture) is extremely important to the preservation of photographic materials. Temperature should be maintained at or below (the lower the better); an "often-recommended" compromise between preservation needs and human comfort is (storage-only areas should be kept cooler). Temperature is the controlling factor in the stability of contemporary color photographs. For color photographs, storage at low temperatures ( or below) is recommended.Library of Congress, ''Caring for Your Photographic Collections'', accessed August 12, 2011, https://www.loc.gov/preservation/care/photo.html. Relative humidity should be maintained at 30–50% without cycling more than +/- 5% a day. The lower part of that range is best for "long term stability of several photographic processes". Not only do relative humidity levels above 60% cause deterioration, but also low and fluctuating humidity may also damage them. Climate control equipment can be used to control temperatures and humidity. Air conditioners, dehumidifiers, and humidifiers can be helpful, but it is important to make sure they help instead of hurt (for example, air conditioning raises humidity).


Cold storage

Cold storage is recommended for especially vulnerable materials. Original prints, negatives, and transparencies (not glass plates, daguerreotypes, ambrotypes, tintypes, or other images on glass or metal) should be placed in packaging (archival folders in board boxes in double freezer weight Ziplock bags) in cold storage, and temperatures should be maintained at .National Park Service, "Caring for Photographs: General Guidelines", Conserve-O-Gram 14, no. 4 (June 1997), accessed August 12, 2011

According to the guideline of National Archives facilities, clear plastic bags such as Zip-locks or flush-cut bags with twist-ties (polyethylene or polypropylene plastic bags) and cotton gloves are needed.Sarah S. Wagner, ''Cold Storage Handling Guidelines for Photographs'' (1991), accessed August 12, 2011, https://www.archives.gov/preservation/storage/cold-storage-photos.html. Removing items from cold storage requires letting them acclimate to room conditions. Photographs must be allowed to warm up slowly in a cool, dry place, such as an office or processing area. Original items should be retrieved from the storage only in an emergency and no more than once a year. Without cold storage, temperature-sensitive materials will deteriorate in a matter of a few decades; with cold storage they can remain unchanged for many centuries.


Light control

Photographs should not be hung near light. Hanging photographs on a wall can cause damage from the exposure to direct sunlight, or to fluorescent lights. Displays of photographs should be changed periodically because most photographs will deteriorate in light over time. UV-absorbing sleeves can be used to filter out damaging rays from fluorescent tubes and UV- absorbing sheets can be placed over windows or in frames. Low UV-emitting bulbs are available. Light levels should be kept at 50–100 Lux (5–10 footcandles) for most photographs when in use for research as well as exhibit. Exposure of color slides to the light in the projector should be kept to a minimum, and photographs should be stored in dark storage. The best way to preserve a photograph is to display a facsimile.


Pollution control

Controlling air quality is difficult. Ideally, air entering a storage or exhibition area should be filtered and purified. Gaseous pollution should be removed with chemical filters or wet scrubbers. Exterior windows should be kept when possible. Interior sources of harmful gases should be minimized. Metal cabinets are preferable to wooden cabinets, which can produce harmful peroxides. Air can be filtered to keep out gaseous pollutants and particulates such as nitrogen dioxide, sulphur dioxide, hydrogen sulfide, and ozone. Air filters must be changed regularly to be effective. Air circulation should also be checked periodically.


Handling control

Handling and use policies should be established and staff should be trained in policies and policy enforcement and telling users the policies when they arrive. Policies for processing, handling for loaned or exhibited items, and disaster prevention and recovery should also be created and followed. Work spaces should be clean and uncluttered. Clean gloves or clean, dry hands should be used whenever photographs are handled. Foods, drink, dirt, cleaning chemicals, and photocopy machines should be kept away from photo storage, exhibit, or work spaces. For precious materials, users should be provided with duplicates, not originals.


Storage systems control

Proper storage materials are essential for the long-term stability of photographs and negatives. Enclosures keep away dirt and pollutants. All enclosures used to house photographs and those should meet the specifications provided in the International Organization for Standardization (ISO). Most photographs can be safely kept in paper enclosures; some can also be safely stored in some types of plastic enclosures.Icon, The Institute of Conservation, ‘’Care and conservation of photographic materials’’ (2006), accessed August 12, 2011, http://www.conservationregister.com/carephotographs.asp . Paper enclosures protect objects from light, but may result in increased handling for viewing. Paper enclosures must be acid-free, lignin-free, and are available in both buffered (alkaline, pH 8.5) and unbuffered (neutral, pH 7) stock. Storage materials must pass the ANSI Photographic Activity Test (PAT) which is noted in suppliers’ catalogs. Paper enclosures also protects the photographs from the accumulation of moisture and detrimental gases and are relatively inexpensive. Plastic enclosures include uncoated polyester film, uncoated cellulose triacetate, polyethylene, and polypropylene. Plastic enclosures are transparent. Photographs can be viewed without removal from the enclosure, thus it can reduce handling. However, plastic enclosures can trap moisture and cause ferrotyping (sticking, with a resultant glossy area). Plastic is not suitable for prints with surface damage, glass or metal-based photographs, nor for film-based negatives and transparencies from the 1950s, unless the latter are in cold storage. It should not to be used to store older safety film negatives as this may hasten their deterioration. Horizontal storage is preferable for many photographic prints and oversize photographs. It provides overall support to the images and prevents mechanical damage such as bending. Vertical storage is often more efficient and may make access to a collection easier. Materials of similar size should be stored together. Boxes and files should not be overcrowded.


Reproduction and digitization

Unlike the digital photography, born-digital photographs that are widely produced and consumed today, historical photographs such as old slides, films, and printed photos are not easy to preserve. An important component of long-term photograph preservation is making reproductions (by photocopying, photographing, or scanning and digitizing) of photographs for use in exhibitions and by researchers, which reduces the damage caused by non-controlled environments and handling. Digitizing photographs also allows access by a much wider public, especially where the images have intrinsic historic value. Digital scans, however, are not replacements for the original, as digital file formats may become obsolete. Originals should always be preserved, even if they have been digitized. Born-digital photographs also require preservation, using
digital preservation In library science, library and archival science, digital preservation is a formal process to ensure that digital information of continuing value remains accessible and usable in the long term. It involves planning, resource allocation, and appli ...
techniques.
Safeguarding European Photographic Images for Access (SEPIA)
lists ten principles for digitization of historical photograph. Summarized, they are: # Photographs are an essential part of our cultural heritage, which contain our past, documentary and artistic value and the history of photographic processes; # Digitizing photographs that deteriorate quickly is urgent matter to facilitate access for a large audience; # Since digitization is not an end itself but a tool, selection of photographs to digitize should be based on an understanding of the nature and potential use of the collection; # It's essential to define the aims, priorities, technical requirements, procedures and future use for investments; # The creation of a digital image is a sophisticated activity which requires photographic expertise with ethical judgment; # Digital images need regular maintenance in order to keep pace with changing technologies; # A good digitization project requires teamwork, combining expertise on imaging, collection management, IT, conservation, descriptive methods and preservation strategies; # The input of specialists in every project is essential to integrate preservation measures in the work-flow, handle fragile materials and avoid damage to the originals; # Preservation specialists need to manage of digital assets in line with the overall preservation policy of the organization; and # Museums, archives and libraries actively involve to develop international standards for the preservation of digital collections in the long-term view.


Examples

An example of digitization as part of a photograph preservation strategy is the photographic collection of the Tay Bridge disaster of 1879. These photographs have been digitized and disseminated more widely. Only the positive prints survive, owing to the widespread practice of recycling the original glass negatives to reclaim the
silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...
content. Even when carefully preserved and kept in the dark, damage can occur through intermittent exposure to light, as shown by damage to the image of the intact bridge (at left). An example of a larger digitization project is th
Cased Photographs Project
which provides access to digital images and detailed descriptions of daguerreotypes, ambrotypes, tintypes, and related photographs in the collections of the
Bancroft Library The Bancroft Library is the primary special-collections library of the University of California, Berkeley. It was acquired from its founder, Hubert Howe Bancroft, in 1905, with the proviso that it retain the name Bancroft Library in perpetuity. ...
and the
California State Library The California State Library is the state library of the State of California, founded in 1850 by the California State Legislature. The Library collects, preserves, generates and disseminates a wide array of information. Today, it is the central ...
.


Conservation treatments

Photograph conservation involves the physical treatment of individual photographs. As defined by the
American Institute for Conservation The American Institute for Conservation (AIC) is a national membership organization of conservation professionals, headquartered in Washington, D.C. History The AIC first launched in 1972 with only a handful of members. Now it is grown to ove ...
, treatment is "the deliberate alteration of the chemical and/or physical aspects of cultural property, aimed primarily at prolonging its existence. Treatment may consist of stabilization and/or restoration." Stabilization treatments aim to maintain photographs in their current condition, minimizing further deterioration, while restoration treatments aim to return photographs to their original state. Conservation treatments range from very simple tear repairs or flattening to more complex treatments such as stain removal. Treatments vary widely depending on the type of photograph and its intended use. Therefore, conservators must by knowledgeable regarding both of these issues. Guides for the preservation of personal and family photograph collections, such as Cornell University'
''Preserving Your Family Photographs''
and the AIC's ''Caring for Your Treasures'', recommend that people contact a trained conservator if they have rapidly deteriorating negatives or photographs with active mold growth, staining from pressure sensitive tape, severe tears, adhesion to enclosures, and other types of damage requiring conservation treatment.


Professional organizations

There are a number of international organizations concerned with conservation of photographs along with other subjects, including the
International Council on Archives The International Council on Archives (ICA; French: ''Conseil international des archives'') is an international non-governmental organization which exists to promote international cooperation for archives and archivists. It was set up in 1948, w ...
(ICA), th
International Institute for Conservation of Historic and Artistic Works (IIC)
and th
International Council of Museums - Committee for Conservation (ICOM-CC)
Th
Photographic Records Working Group
is a specialty group within the ICOM-CC. In the United States, the national membership organization of conservation professionals is th
American Institute for Conservation of Historic and Artistic works (AIC)
to which th
Photographic Materials Group (PMG)
belongs. The
Northeast Document Conservation Center The Northeast Document Conservation Center (NEDCC) was founded in 1973. It is the first non-profit conservation center in the United States to specialize in the preservation of paper-based library and archival materials. NEDCC was initiated by t ...
(NEDCC) and the
Conservation Center for Art and Historic Artifacts The Conservation Center for Art & Historic Artifacts (CCAHA), located in Philadelphia, Pennsylvania, was founded by Marilyn Kemp Weidner in 1977, with funding from thNational Endowment for the Humanitiesand in response to the growing problem of pa ...
(CCAHA) also play an important role in the field of conservation. The
Image Permanence Institute The Image Permanence Institute (IPI) is a university-based, non-profit research laboratory devoted to scientific research in the preservation of visual and other forms of recorded information. It is the world's largest independent laboratory with ...
(IPI) at Rochester Institute of Technology is one of the leaders in preservation research of images in particular.


Codes and standards

Photograph conservators and preservation managers are guided in their work by codes of ethics and technical standards. The
International Council on Archives The International Council on Archives (ICA; French: ''Conseil international des archives'') is an international non-governmental organization which exists to promote international cooperation for archives and archivists. It was set up in 1948, w ...
publishes a ''Code of Ethics'' an
''Guidelines for Practice''
Additionally, members of other professions (such as archivists and librarians) who deal with preservation of photographs do so in accordance with their professional organization's codes of ethics. For example, the
Society of American Archivists The Society of American Archivists is the oldest and largest archivist Voluntary association, association in North America, serving the educational and informational needs of more than 5,000 individual archivist and institutional members. Establi ...
''Code of Ethics'' states that "Archivists protect all documentary materials for which they are responsible and guard them against defacement, physical damage, deterioration, and theft." The
International Organization for Standardization The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. M ...
(ISO) and
American National Standards Institute The American National Standards Institute (ANSI ) is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organiz ...
(ANSI) both publish technical standards that govern the materials and procedures used in photograph preservation and conservation. The
International Federation of Library Associations and Institutions The International Federation of Library Associations and Institutions (IFLA) is an international body representing the interests of people who rely on Library, libraries and information professionals. A non-governmental, not-for-profit organizati ...
has published a list of ANSI standards pertaining to the care and handling of photographs.


Education and training

Photograph conservators can be found in museums, archives, and libraries, as well as in private practice. Conservators often have earned their master's degrees in
art conservation conservation and restoration of cultural property focuses on protection and care of cultural property (tangible cultural heritage), including artworks, architecture, archaeology, and museum collections. Conservation activities include preve ...
, though many have also been trained through
apprenticeship Apprenticeship is a system for training a potential new practitioners of a trade or profession with on-the-job training and often some accompanying study. Apprenticeships may also enable practitioners to gain a license to practice in a regulat ...
. They often have backgrounds in
art history Art history is the study of Work of art, artistic works made throughout human history. Among other topics, it studies art’s formal qualities, its impact on societies and cultures, and how artistic styles have changed throughout history. Tradit ...
, chemistry, or photography. Among numerous programs concerned with conservation of photographs around the world are:
University of AmsterdamUniversity of Melbourne in AustraliaThe Royal Danish Academy of Fine ArtsCanadian Conservation InstituteThe National School of Conservation, Restoration and Museology in Mexico (ENCRyM)Royal Institute for the Study and Conservation of Belgium's Artistic HeritageInstitut national du patrimoineUniversité Paris 1Hochschule für Technik und Wirtschaft Berlin (HTW)Fachhochschule KölnStaatlichen Akademie der Bildenden Künste StuttgartSwiss Conservation-Restoration CampusHochschule der Künste BernFratelli AlinariRoyal College of Art/Victoria and Albert Museum

The International master Program in Conservation of Antique Photographs and Paper Heritage held at the EICAP Faculty of Applied arts-Helwan University
In addition
Getty Conservation Institute (GCI)
works internationally to advance conservation practice in the visual arts. The United States, in particular, has many training or degree programs for photograph conservators offered by graduate schools and organizations such as:
Conservation Center for Art and Historic Artifacts (CCAHA)Northeast Document Conservation Center (NEDCC)George Eastman HouseBuffalo State CollegeInstitute of Fine Arts, New York UniversityUniversity of DelawareSmithsonian Center for Materials Research and Education
There are also photographic conservation teaching courses available online from various providers, for instance:
Conserve Photography online teaching coursesCitaliarestauro.com online teaching courseNEDCC online teaching course


Storing photos at home

A photobook or
photo album A photographic album or photo album, is a series of photographic prints collected by an individual person or family in the form of a book. Some book-form photo albums have compartments which the photos may be slipped into, usually made out of pl ...
is a series of photographic prints collected by an individual or family in the form of a book. Some book-shaped photo albums have compartments into which photos can be inserted, usually made of plastic; other albums have heavy abrasive paper covered with clear plastic sheets on which photos can be placed. Earlier albums were often simply books of heavy paper, on which photographs could be glued or attached using adhesive corners or pages. From the point of view of professionals, a photo album is not the best way to store photos, especially valuable ones, but family archives are usually preserved in this way. It is recommended that physical images be stored in the following manner: * Archive boxes: store hundreds of images securely, but still be easy to find. * Acid-free albums: protect photos and allow easy viewing at home. Ideal photo storage involves placing each photo in a separate folder made of buffered or
acid-free paper Acid-free paper is paper that, if infused in water, yields a neutral or basic pH (7 or slightly greater). 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-fr ...
. Buffer paper folders are especially recommended for photographs that have been previously adhered to poor quality material or with an adhesive that will cause further acid formation. Store photographs 8x10 inches or smaller vertically along the long edge of the photograph in a buff paper folder in a larger archival box, and label each folder with appropriate information to identify it. The rigid folder protects the photo from sagging or crumpling as long as the box is not too tightly stuffed or insufficiently filled. Stack large photographs or fragile photos flat in archival boxes with other materials of comparable size.


See also

*
Preservation (library and archival science) In Conservation and restoration of cultural property, conservation, Library science, library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making ...
* Conservation and restoration of books, manuscripts, documents and ephemera *
Collections care Disaster preparedness in museums, galleries, libraries, archives and private collections, involves any actions taken to plan for, prevent, respond or recover from natural disasters and other events that can cause damage or loss to cultural prope ...
*
Media preservation Preservation of documents, pictures, recordings, digital content, etc., is a major aspect of archival science. It is also an important consideration for people who are creating time capsules, family history, historical documents, scrapbooks a ...
*
Conservation (cultural heritage) The conservation and restoration of cultural property focuses on protection and care of cultural property, cultural property (tangible cultural heritage), including Collection (artwork), artworks, Architectural conservation, architecture, archae ...
* Conservation and restoration of photographic plates


Notes


Further reading

*Clark, Susie, and Franziska Frey. ''Care of Photographs.'' Amsterdam: European Commission on Preservation and Access, 2003. *Eaton, George T. ''Conservation of Photographs.'' Kodak Publication No. F-40. Rochester, NY: Eastman Kodak Co., 1985. *Hayes, Sandra. "Preserving History: Digital Imaging Methods of Selected Mississippi Archivists." ''Mississippi Archivists'' 65, no. 4 (Winter 2001): 101–102. *Norris, Debra Hess, and Jennifer Jae Gutierrez, eds. ''Issues in the Conservation of Photographs.'' Los Angeles: Getty Conservation Institute, 2010. *Reilly, James. ''Care and Identification of 19th Century Photographic Prints.'' Kodak Publication No. G2S. Rochester, NY: Eastman Kodak Co., 1986. *Ritzenthaler, Mary Lynn and Diane Voght-O'Connor, et al. ''Photographs: Archival Care and Management.'' Chicago: Society of American Archivistis, 2006.


External links


Organizations


The Photographic Materials Group of the American Institute for Conservation

The Advanced Residency Program in Photograph Conservation at the George Eastman House

Notes on Photographs, a Wiki from George Eastman House

The Image Permanence Institute

ICOM-CC Photographic Materials Working Group


Guides



* ttps://web.archive.org/web/20070927210037/http://www.hfmgv.org/explore/artifacts/photo.asp%2C The Care and Preservation of Photographic Prints, The Henry Ford Museumbr>Preservation of Photographs: Select Bibliography, Northeast Document Conservation Center
* ttp://www.imagepermanenceinstitute.org/shtml_sub/consumerguide.pdf A Consumer Guide to Digital and Print Stability, Image Permanence Institute {{Cultural Conservation-Restoration , state=expanded Conservation and restoration of cultural heritage Preservation (library and archival science) Science of photography