Sound recordings or phonograph records preserve information through music and recorded voice and allow such material to remain accessible over time. Recordings have been made on wax and metal cylinders, and on disks made of aluminum, glass, and vinyl. The sound signal is stored within the grooves of recording and is released through a stylus or needle when it is played. It is particularly important to protect these grooves from dirt, dust, and oil, which act as abrasives. In order to protect the grooves of a record and to decrease abrasions, phonographs should be housed in inner sleeves made of either an inert plastic, such as polyethylene, or acid-free paper. They should be stored vertically to avoid warping. Phonograph recordings should be stored in an environment that has a temperature of 68° Fahrenheit (plus or minus 5° Fahrenheit), and a relative humidity that ranges from 40 percent to 55 percent. In addition, a record should be handled by supporting the edge of the record and the paper cover in the center. Phonograph records can be cleaned with a soft lint-free cloth or brush.
Computer Disks, Compact Discs, and DVDs,
Computer disks and compact discs have superseded other types of recording formats for information and data. For example, compact discs (also known as CDs) have essentially replaced phonograph records for recording and distributing music. DVDs (digital video discs or digital versatile discs) have been introduced as a replacement for videotapes and as a way to store large amounts of information. Computer disks, compact discs, and DVDs store information in a digital format. Compact discs and DVDs are created using lasers that burn a sequence of binary code (composed of 0s and 1s) onto the bottom of a disc. Lasers both record and read information from the compact disc or the DVD without direct contact with the surface of the disc.
Computer disks and compact discs are composed of a variety of materials that affect the permanence of the information they hold. They can be affected by high fluctuations in temperature and humidity, as well as dirt and dust. These types of environmental hazards can cause the loss of part of the digital code. Both should be stored away from high temperatures or direct sunlight, and should be housed in dust-free containers. For compact discs, a soft, clean, dry cloth can be used to remove dirt, dust, or fingerprints from the surface of the compact disc. Water, solvents, or sprays are not necessary in order to clean a compact disc. Care must be taken to not scratch or damage the surface of a compact disc or the surface of a computer disk. Compact discs, DVDs, and computer disks should be kept away from magnetic field sources that may corrupt or destroy the information that they contain.
As with video and audio media, computer disks, compact discs, and DVD are dependent on machines to read or access the information they contain. There is also information or computer data that is dependent on a specific type of software for retrieval and access. This means that it is essential to preserve the media as well as the computer equipment and software necessary to access the information. Computer equipment is susceptible to an adverse environment. High temperatures, dampness, and humidity, as well as dust and dirt, can damage computer equipment and destroy the information or data it contains.
Computer technology is constantly changing and many storage formats are no longer in use or available for example, punch cards and 8-inch and 5-inch floppy disks. An option to ensure survival of the information stored on a computer disk, compact disc, or other type of media dependent on a computer is to convert or migrate the information to a new format every three to five years without the loss of intellectual content or the integrity of the information. Creation of digital media mandates a commitment to the maintenance of the format over time.
Facsimiles and Reformatting,
The artifactual value of an object, or its value in its original form, may make it a candidate for conservation and preservation through the creation of a surrogate or facsimile. The use of surrogates prevents further damage to the original item, in whatever form, by allowing the surrogate to be used in place of the original. An object presenting information often has historic or intrinsic value and must be preserved in its original form. Other issues that contribute to the preservation of an artifact in its original form are its age and rarity. Sometimes, and for many reasons, objects or materials cannot be maintained in their original format and in such cases it may be acceptable to copy the content onto an alternative format that preserves the information but not the original format.
Reformatting original materials onto a new media ideally provides an accurate and quality reproduction of the original and allows the information it provides to be accessible over time. This also assures that deteriorating materials are no longer required for use, and those materials that are of significant value but also have the potential to experience further damage will be protected.