Media preservation
Encyclopedia
Preservation
of document, pictures, recordings, digital content, etc., is a major aspect of archival science
. It is also an important consideration for people who are creating time capsule
s, family history
, historical document
s, scrapbook
s and family trees. Common storage media are not permanent, and there are few reliable methods of preserving documents and pictures for the future.
and ordinary color prints
may fade away to nothing in a relatively short period if not stored and handled properly. This happens even if the negatives and prints are kept in the dark, because the ambient light is not the determining factor, but heat and humidity are. Because color processing
results in a less stable image than traditional black-and-white
processing, black-and-white pictures from the 1920s are more likely to survive into the long-term future than color films and photographs from after the middle 20th century. The color degradation is the result of the dyes used in the color processes.
Color prints made on most inkjet printer
s look very good at first but they have a very short lifespan, measured in months rather than in years. Even prints from commercial photo labs will start to fade in a matter of years if not processed properly and stored in cool, dry environments.
Black-and-white photographic films using silver halide
emulsions are the only film types that have proven to last for archival storage. The determining factors for longevity include the film base type, proper processing (develop, stop, fix and wash) and proper storage. Early films were coated onto a nitrate base material which was prone to combustion if stored in uncontrolled temperatures. Nitrate film was replaced with acetate-base films. These Cellulose acetate film
s were later discovered to outgass acids (also referred to as vinegar syndrome). Acetate films were replaced in the early 1980s by polyester
film base materials which have been determined to be more stable than nitrate- and acetate-base films.
s and image scanner
s. Books and manuscripts can also have their information saved without destruction by using a book scanner
.
Where the media need to be preserved, for example if a document is a sketch of crayon by a famous artist on media (say paper) a complex process of preservation may be used, depending on the condition and importance of the item including gluing the media onto more stable media. Other considerations in preserving paper/books may include
versions online. However, digital preservation
for the long-term is still an issue.
Most sites require you to scan the images yourself to your own hard drive and then upload them via their website. The disadvantage to this is that not everyone has the knowledge or the ability to scan images themselves. If you cannot scan the image yourself then you need to arrange for someone else to do it for you.
The alternative is to send all those old photographic prints, slides, negatives and videos off to be digitized and then returned to you. Some sites will return the prints, slides and negatives with a CD on which the digitized images appear.
Most sites will require you to either pay a membership fee or make a purchase of one of the items they sell on their website within a set period of time or your account will be deleted along with your images. So when choosing a photostorage service ensure you read the "fine print" to find out what their conditions are. For images you wish to preserve for generations, storing them in multiple formats may be appropriate, as digital preservation
is not assured by merely posting photos on a photo site.
such as audio and videotape
s have a very limited life span.
According to digital storage experts, media such as zip disks, CDs, or DVD
s last only a definite period before they begin to degrade, although the fact that these media formats are recent inventions combined with a high rate of change and improvements in these technologies makes it difficult to determine how long digital media will last. Manufacturers claim minimum lifetimes of 50 years for CD-Rs and 25 years for CD-RWs. These experts suggest that digital images be transferred as new media are developed to ensure that they are preserved.
Audio and video tapes require specific care and handling to ensure that the recorded information will be preserved. For information that must be preserved indefinitely, periodic transcription from old media to new ones is necessary, not only because the media are unstable but also because the recording technology may become obsolete.
The magnitude of the problem of magnetic tape deterioration is just starting to be realized. According to some research, there is a good chance that magnetic tape older than 10 years will deteriorate. The threat comes from several sources, but the largest threat is chemical in nature, coming from the breakdown of the binder
, or glue, that holds the magnetic particles to the polyester base of the tape. As this occurs, the tape often gets coated with a tenacious adhesive that makes it extremely difficult to play. Tapes which have been stored in hot, humid conditions is particularly vulnerable to this phenomenon. In some cases the problem can be so severe that the magnetic material literally falls off or sheds from the base, leaving a pile of dust and clear backing. Before the problem becomes so advanced, archivist
s can bake the tape
and make a new copy. Alternately, a digitally encoded copy of the tape can be made, so that its content can be preserved indefinitely as a digital data file.
This problem has been known for some time, but the extent of both the problem and the catastrophic effect it has on magnetic media is just now gaining visibility. It is also common for computer floppy disks to degrade over time, as the lubricants inside the plastic jackets of many older floppies promote the decay of the magnetic medium. Also, the alignment of the magnetic particles of the disk substrate may gradually degrade, leading to a loss of formatting and data. Early laserdisk media were prone to degradation as the layers of the disk substrate were bonded with an adhesive that was vulnerable to decay and would crumble over time. This would lead the different layers of the disk to peel apart, damaging the pitted data surface and rendering the disk unreadable.
Media at risk include recorded media such as master
audio recordings of symphonies and videotape recordings of the news gathered over the last 40 years. Threats to media that must be considered when archiving important record media include accidental erasure, physical loss due to disasters such as fires and floods, and media degradation.
Along with the actual media being degraded over the years, the machines that are available to play back or reproduce the audio sources are becoming archaic themselves. Manufacturers and their support (parts, technical updates) for their machines have disappeared throughout the years. Even if the medium is vaulted and archived correctly, the mechanical properties of the machines have deteriorated to the point that they could do more harm than good to the tape or disc being played.
Many major film studios are now backing up their libraries by converting them to electronic media files, such as .AIFF or .WAV-based files via digital audio workstations. That way, even if the digital platform manufacturer goes out of business or no longer supports their product, the files can still be played on any common computer.
There is a detailed process that must take place previous to the final archival product now that a digital solution is in place. Sample rates and their conversion and reference speed are both critical in this process.
Preservation (library and archival science)
Preservation is a branch of library and information science concerned with maintaining or restoring access to artifacts, documents and records through the study, diagnosis, treatment and prevention of decay and damage....
of document, pictures, recordings, digital content, etc., is a major aspect of 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...
. It is also an important consideration for people who are creating time capsule
Time capsule
A time capsule is an historic cache of goods or information, usually intended as a method of communication with future people and to help future archaeologists, anthropologists, or historians...
s, family history
Family history
Family history is the systematic narrative and research of past events relating to a specific family, or specific families.- Introduction :...
, historical document
Historical document
Historical documents are documents that contain important information about a person, place, or event.Most famous historical documents are either laws, accounts of battles , or the exploits of the powerful...
s, scrapbook
Scrapbook
Scrapbook can refer to:* Scrapbooking, the process of making a scrapbook* Scrapbook , a Mac OS application* Scrapbook , a Switchblade Symphony album* Scrapbook * ScrapBook, a Firefox extension...
s and family trees. Common storage media are not permanent, and there are few reliable methods of preserving documents and pictures for the future.
Paper/prints (photos)
Color negativesNegative (photography)
In photography, a negative may refer to three different things, although they are all related.-A negative:Film for 35 mm cameras comes in long narrow strips of chemical-coated plastic or cellulose acetate. As each image is captured by the camera onto the film strip, the film strip advances so that...
and ordinary color prints
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...
may fade away to nothing in a relatively short period if not stored and handled properly. This happens even if the negatives and prints are kept in the dark, because the ambient light is not the determining factor, but heat and humidity are. Because color processing
Color photography
Color photography is photography that uses media capable of representing colors, which are traditionally produced chemically during the photographic processing phase...
results in a less stable image than traditional 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...
processing, black-and-white pictures from the 1920s are more likely to survive into the long-term future than color films and photographs from after the middle 20th century. The color degradation is the result of the dyes used in the color processes.
Color prints made on most 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 look very good at first but they have a very short lifespan, measured in months rather than in years. Even prints from commercial photo labs will start to fade in a matter of years if not processed properly and stored in cool, dry environments.
Black-and-white photographic films using silver halide
Silver halide
A silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and three forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
emulsions are the only film types that have proven to last for archival storage. The determining factors for longevity include the film base type, proper processing (develop, stop, fix and wash) and proper storage. Early films were coated onto a nitrate base material which was prone to combustion if stored in uncontrolled temperatures. Nitrate film was replaced with acetate-base films. These Cellulose acetate film
Cellulose acetate film
Cellulose acetate film, or safety film, is used in photography as a base material for photographic emulsions. It was introduced in the early 20th century by film manufacturers as a safe film base replacement for unstable and highly flammable nitrate film....
s were later discovered to outgass acids (also referred to as vinegar syndrome). Acetate films were replaced in the early 1980s by 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...
film base materials which have been determined to be more stable than nitrate- and acetate-base films.
Documents/Books
With documents for which the media are not so critical as what the documents contain, the information in documents can be copied by using photocopierPhotocopier
A photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process using heat...
s and image scanner
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
s. Books and manuscripts can also have their information saved without destruction by using a book scanner
Book scanning
Book scanning is the process of converting physical books and magazines into digital media such as images, electronic text, or electronic books by using an image scanner....
.
Where the media need to be preserved, for example if a document is a sketch of crayon by a famous artist on media (say paper) a complex process of preservation may be used, depending on the condition and importance of the item including gluing the media onto more stable media. Other considerations in preserving paper/books may include
- damaging lightLightLight 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...
particularly UV light, which fades and destroys media over time by breaking down the molecules. - atmosphereAtmosphereAn atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
contains small traces of sulfur dioxideSulfur dioxideSulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
and nitric acidNitric acidNitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
which turn media yellow and break the fibers down. - humidityHumidityHumidity 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 moistureMoistureHumidity is the amount of moisture the air can hold before it rains. Moisture refers to the presence of a liquid, especially water, often in trace amounts...
also aid in the breakdown of media. Too much used, the document is attacked by bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and too little used, celluloseCelluloseCellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
material breaks down. - TemperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, particularly elevated ones, can destroy some media. Low temperatures can cause the water to form crystals which expands destroying the fiberFiberFiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
structure of paperPaperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
based documents.
Online Photo Albums
There are now a number of websites that will allow you to upload photos and videos. Sites such as Snap Fish,Fotki, and Flickr are helping people store digitalDigitizing
Digitizing or digitization is the representation of an object, image, sound, document or a signal by a discrete set of its points or samples. The result is called digital representation or, more specifically, a digital image, for the object, and digital form, for the signal...
versions online. However, digital preservation
Digital preservation
Digital preservation is the set of processes, activities and management of digital information over time to ensure its long term accessibility. The goal of digital preservation is to preserve materials resulting from digital reformatting, and particularly information that is born-digital with no...
for the long-term is still an issue.
Most sites require you to scan the images yourself to your own hard drive and then upload them via their website. The disadvantage to this is that not everyone has the knowledge or the ability to scan images themselves. If you cannot scan the image yourself then you need to arrange for someone else to do it for you.
The alternative is to send all those old photographic prints, slides, negatives and videos off to be digitized and then returned to you. Some sites will return the prints, slides and negatives with a CD on which the digitized images appear.
Most sites will require you to either pay a membership fee or make a purchase of one of the items they sell on their website within a set period of time or your account will be deleted along with your images. So when choosing a photostorage service ensure you read the "fine print" to find out what their conditions are. For images you wish to preserve for generations, storing them in multiple formats may be appropriate, as digital preservation
Digital preservation
Digital preservation is the set of processes, activities and management of digital information over time to ensure its long term accessibility. The goal of digital preservation is to preserve materials resulting from digital reformatting, and particularly information that is born-digital with no...
is not assured by merely posting photos on a photo site.
Magnetic media, video cassettes, tapes, hard drives
As with CDs and computer hard drives, Magnetic mediaMagnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
such as audio and videotape
Videotape
A videotape is a recording of images and sounds on to magnetic tape as opposed to film stock or random access digital media. Videotapes are also used for storing scientific or medical data, such as the data produced by an electrocardiogram...
s have a very limited life span.
According to digital storage experts, media such as zip disks, CDs, or DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
s last only a definite period before they begin to degrade, although the fact that these media formats are recent inventions combined with a high rate of change and improvements in these technologies makes it difficult to determine how long digital media will last. Manufacturers claim minimum lifetimes of 50 years for CD-Rs and 25 years for CD-RWs. These experts suggest that digital images be transferred as new media are developed to ensure that they are preserved.
Audio and video tapes require specific care and handling to ensure that the recorded information will be preserved. For information that must be preserved indefinitely, periodic transcription from old media to new ones is necessary, not only because the media are unstable but also because the recording technology may become obsolete.
The magnitude of the problem of magnetic tape deterioration is just starting to be realized. According to some research, there is a good chance that magnetic tape older than 10 years will deteriorate. The threat comes from several sources, but the largest threat is chemical in nature, coming from the breakdown of the binder
Binder
The reaper-binder, or binder, was a farm implement that improved upon the reaper. The binder was invented in 1872 by Charles Withington. In addition to cutting the small-grain crop, it would also tie the stems into small bundles, or sheaves...
, or glue, that holds the magnetic particles to the polyester base of the tape. As this occurs, the tape often gets coated with a tenacious adhesive that makes it extremely difficult to play. Tapes which have been stored in hot, humid conditions is particularly vulnerable to this phenomenon. In some cases the problem can be so severe that the magnetic material literally falls off or sheds from the base, leaving a pile of dust and clear backing. Before the problem becomes so advanced, 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...
s can bake the tape
Tape baking
Tape baking is a process that is used to restore magnetic tapes: audio cassettes and video tapes that have begun to go through a chemical breakdown due to age, known informally as shedding...
and make a new copy. Alternately, a digitally encoded copy of the tape can be made, so that its content can be preserved indefinitely as a digital data file.
This problem has been known for some time, but the extent of both the problem and the catastrophic effect it has on magnetic media is just now gaining visibility. It is also common for computer floppy disks to degrade over time, as the lubricants inside the plastic jackets of many older floppies promote the decay of the magnetic medium. Also, the alignment of the magnetic particles of the disk substrate may gradually degrade, leading to a loss of formatting and data. Early laserdisk media were prone to degradation as the layers of the disk substrate were bonded with an adhesive that was vulnerable to decay and would crumble over time. This would lead the different layers of the disk to peel apart, damaging the pitted data surface and rendering the disk unreadable.
Media at risk include recorded media such as master
Master recording
A multitrack recording master tape, disk or computer files on which productions are developed for later mixing, is known as the multi-track master, while the tape, disk or computer files holding a mix is called a mixed master.It is standard practice to make a copy of a master recording, known as...
audio recordings of symphonies and videotape recordings of the news gathered over the last 40 years. Threats to media that must be considered when archiving important record media include accidental erasure, physical loss due to disasters such as fires and floods, and media degradation.
Along with the actual media being degraded over the years, the machines that are available to play back or reproduce the audio sources are becoming archaic themselves. Manufacturers and their support (parts, technical updates) for their machines have disappeared throughout the years. Even if the medium is vaulted and archived correctly, the mechanical properties of the machines have deteriorated to the point that they could do more harm than good to the tape or disc being played.
Many major film studios are now backing up their libraries by converting them to electronic media files, such as .AIFF or .WAV-based files via digital audio workstations. That way, even if the digital platform manufacturer goes out of business or no longer supports their product, the files can still be played on any common computer.
There is a detailed process that must take place previous to the final archival product now that a digital solution is in place. Sample rates and their conversion and reference speed are both critical in this process.
See also
- Preservation (library and archival science)Preservation (library and archival science)Preservation is a branch of library and information science concerned with maintaining or restoring access to artifacts, documents and records through the study, diagnosis, treatment and prevention of decay and damage....
- Preservation of magnetic audiotapePreservation of magnetic audiotapeThere are multiple types of magnetic media, however this article focuses on recommended best practices for handling, cleaning and storage of magnetic audiotapes in an archival repository, either in the form of open reels or enclosed cassettes...