.
In general, these can occur at the same time, though they are conceptually distinct.
A series of digital integers can be transformed into an analog output that approximates the original analog signal. Such a transformation is called a DA conversion. The sampling rate and the number of bits used to represent the integers combine to determine how close such an approximation to the analog signal a digitization will be.
Main article:
In the context of libraries, archives, and museums, digitization is a means of creating digital surrogates of analog materials, such as books, newspapers, microfilm and videotapes, offers a variety of benefits, including increasing access, especially for patrons at a distance; contributing to collection development, through collaborative initiatives; enhancing the potential for research and education; and supporting preservation activities.
[16] Digitization can provide a means of preserving the content of the materials by creating an accessible facsimile of the object in order to put less strain on already fragile originals. For sounds, digitization of legacy analog recordings is essential insurance against technological obsolescence.
[17] A fundamental aspect of planning digitization projects is to ensure that the digital files themselves are preserved and remain accessible;
[18] the term "
digital preservation," in its most basic sense, refers to an array of activities undertaken to maintain access to digital materials over time.
[19]
The prevalent Brittle Books issue facing libraries across the world is being addressed with a digital solution for long term book preservation.[20] Since the mid-1800s, books were printed on wood-pulp paper, which turns acidic as it decays. Deterioration may advance to a point where a book is completely unusable. In theory, if these widely circulated titles are not treated with de-acidification processes, the materials upon those acid pages will be lost. As digital technology evolves, it is increasingly preferred as a method of preserving these materials, mainly because it can provide easier access points and significantly reduce the need for physical storage space.
Cambridge University Library is working on the Cambridge Digital Library, which will initially contain digitised versions of many of its most important works relating to science and religion. These include examples such as Isaac Newton's personally annotated first edition of his Philosophiæ Naturalis Principia Mathematica[21] as well as college notebooks[22][23] and other papers,Brittle Books issue facing libraries across the world is being addressed with a digital solution for long term book preservation.[20] Since the mid-1800s, books were printed on wood-pulp paper, which turns acidic as it decays. Deterioration may advance to a point where a book is completely unusable. In theory, if these widely circulated titles are not treated with de-acidification processes, the materials upon those acid pages will be lost. As digital technology evolves, it is increasingly preferred as a method of preserving these materials, mainly because it can provide easier access points and significantly reduce the need for physical storage space.
Cambridge University Library is working on the Cambridge Digital Library, which will initially contain digitised versions of many of its most important works relating to science and religion. These include examples such as Isaac Newton's personally annotated first edition of his Philosophiæ Naturalis Principia Mathematica[21] as well as college notebooks[22][23] and other papers,[24] and some Islamic manuscripts such as a Quran[25] from Tipu Sahib's library.
Google, Inc. has taken steps towards attempting to digitize every title with "Google Book Search".[26] While some academic libraries have been contracted by the service, issues of copyright law violations threaten to derail the project.[27] However, it does provide – at the very least – an online consortium for libraries to exchange information and for researchers to search for titles as well as review the materials.
There is a common misconception that to digitize something is the same as digital preservation. To digitize something is to convert something from an analog into a digital format.[28] An example would be scanning a photograph and having a digital copy on a computer. This is essentially the first step in digital preservation. To digitally preserve something is to maintain it over a long period of time.[29][30]
Digital preservation is more complicated because technology changes so quickly that a format that was used to save something years ago may become obsolete, like a 5 1/4" floppy drive. Computers are no longer made with them, and obtaining the hardware to convert a file from an obsolete format to a newer one can be expensive. As a result, the upgrading process must take place every 2 to 5 years,[31] or as newer technology becomes affordable, but before older technology becomes u
Digital preservation is more complicated because technology changes so quickly that a format that was used to save something years ago may become obsolete, like a 5 1/4" floppy drive. Computers are no longer made with them, and obtaining the hardware to convert a file from an obsolete format to a newer one can be expensive. As a result, the upgrading process must take place every 2 to 5 years,[31] or as newer technology becomes affordable, but before older technology becomes unobtainable. The Library of Congress provides numerous resources and tips for individuals looking to practice digitization and digital preservation for their personal collections.[32]
Digital preservation can also apply to born-digital material. An example of something that is born-digital is a Microsoft Word document saved as a .docx file or a post to a social media site. In contrast, digitization only applies exclusively to analog materials. Born-digital materials present a unique challenge to digital preservation not only due to technological obsolescence but also because of the inherently unstable nature of digital storage and maintenance. Most websites last between 2.5 and 5 years, depending on the purpose for which they were designed.[33]
Many libraries, archives, and museums, as well as other institutions, struggle with catching up and staying current in regards to both digitization and digital preservation. Digitization is a time-consuming process, particularly depending on the condition of the holdings prior to being digitized. Some materials are so fragile that undergoing the process of digitization could damage them irreparably; light from a scanner can damage old photographs and documents. Despite potential damage, one reason for digitizing some materials is because they are so heavily used that digitization will help to preserve the original copy long past what its life would have been as a physical holding.
Digitization can also be quite expensive. Institutions want the best image quality in digital copies so that when they are converted from one format to another over time only a high-quality copy is maintained. Smaller institutions may not be able to afford such equipment. Manpower at many facilities also limits how much material can be digitized. Archivists and librarians must have an idea of what their patrons wish to see most and try to prioritize and meet those needs digitally.
Labour resources and funding also limit digital preservation in many institutions. The cost of upgrading hardware or software every few years can be prohibitively expensive. Training is another issue since many librarians and archivists do not have a computer science background. Intellectual control of digital holdings presents yet another issue that sometimes occurs when the physical holdings have not yet been entirely processed. One suggested timeframe for completely transcribing digital holdings was every ten to twenty years, making the process an ongoing and time-consuming one.
Finally preserving digitized assets over long periods of time is challenging. Essentially you are storing a massive set of 1s and 0s. These signals can be physically burned onto media, like CDs, or stored magnetically, on hard drives. In either case, the storage mechanisms degrade over time. The physical materials degrade until the 1s or 0 marks can no longer be made out. The magnetic media degrades and loses its charge. If you alter just one 1 or one 0, you can significantly alter the recording. Thus data integrity with digitized assets in storage is a big challenge.
Digital reformatting is the process of converting analog materials into a digital format as a surrogate of the original. The digital surrogates perform a preservation function by reducing or eliminating the use of the original. Digital reformatting is guided by established best practices to ensure that materials are being converted at the highest quality.
Digital reformatting at the Library of Congress
Audio media offers a rich source of historic ethnographic information, with the earliest forms of recorded sound dating back to 1890.[37] Ac
The Library of Congress has constituted a Preservation Digital Reformatting Program.[36] The Three main components of the program include:
Audio media offers a rich source of historic ethnographic information, with the earliest forms of recorded sound dating back to 1890.[37] According to the International Association of Sound and Audiovisual Archives (IASA), these sources of audio data, as well as the aging technologies used to play them back, are in imminent danger of permanent loss due to degradation and obsolescence.[38] These primary sources are called “carriers” and exist in a variety of formats, including wax cylinders, magnetic tape, and flat discs of grooved media, among others. Some formats are susceptible to more severe, or quicker, degradation than others. For instance, lacquer discs suffer from delamination. Analog tape may deteriorate due to sticky shed syndrome.
