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Records Authority
Category: Digital Preservation

Preservation Master

Also known as: Preservation Copy
Simply put

A preservation master is a high-quality version of a record created to safeguard its informational content when the original is at risk of being lost, often through physical deterioration. It is intended to serve as the reliable, protected source from which other copies can be made, rather than as an everyday working copy.

Formal definition

A preservation master is a product category produced when original records are at risk of loss of information, typically due to deterioration or other threats to the original carrier. It functions as the authoritative preserved version whose purpose is to maintain the integrity and usability of a record's content over time; it is generally distinguished from access or use copies derived from it. The specific creation methods, formats, and handling standards for a preservation master depend on the nature of the material and on organizational or institutional policy, and this definition does not extend to the broader disposition, retention, or transfer decisions that determine whether a record warrants preservation in the first place.

Why it matters

Records held on physical or aging digital carriers are vulnerable to deterioration and other threats that can result in the permanent loss of their informational content. A preservation master addresses this risk by creating a high-quality, protected version whose primary purpose is to safeguard the content of an at-risk original rather than to serve as an everyday working copy. Without such a copy, an organization may find that continued handling, use, or the physical decay of the original leads to irreversible loss of the record's evidential and informational value.

Maintaining a distinct preservation master also supports the properties that make something an authoritative record, including its integrity and usability over time. By separating the protected source version from the access or use copies made for routine consultation, organizations reduce the wear and exposure of the material that carries the record's content. This separation helps ensure that a reliable version remains available from which further copies can be generated as needed.

It is important to note the boundaries of this concept. The existence of a preservation master concerns how a record's content is protected once a decision to preserve has been made; it does not by itself determine whether a record warrants preservation. Those broader disposition, retention, and transfer decisions are governed by separate organizational policy and, in many cases, by jurisdiction- and sector-specific requirements that fall outside the scope of this term.

Who it's relevant to

Archivists and preservation specialists
Those responsible for safeguarding at-risk records rely on the concept to distinguish a protected, authoritative source version from the access copies used for consultation, and to apply creation methods and handling standards suited to the material.
Records managers
Records managers concerned with maintaining the integrity and usability of records over time may need to ensure that a reliable preservation master exists for content at risk of loss, while recognizing that decisions about whether a record warrants preservation are governed separately by policy and applicable requirements.
Information governance officers
Governance leads coordinating policy across preservation, risk, and value benefit from understanding where preservation activity fits relative to broader disposition, retention, and transfer decisions, since the preservation master addresses how content is protected rather than whether it should be kept.

Inside Preservation Master

Authoritative source copy
The preservation master is typically the highest-quality, most complete version of a digital object retained for long-term keeping, from which access or derivative copies are generated. It is intended to serve as the reference point against which other copies can be verified.
Fixity information
Data such as checksums or hashes associated with the master that allows the integrity of the object to be monitored over time and any corruption or unauthorized change to be detected.
Preservation metadata
Descriptive, structural, technical, and provenance metadata bound to or associated with the master, supporting its authenticity, reliability, and usability across its retained life. The precise metadata model applied often depends on organizational policy and the standards adopted.
Format and technical characteristics
Information about the file format, encoding, and technical dependencies of the object, which informs preservation planning such as future migration or emulation. Preferred preservation formats vary by institution and are typically defined in policy.
Relationship to derivative copies
The master is generally distinguished from access, service, or working copies. Derivatives are produced for use and dissemination, while the master is protected and not routinely accessed, which helps preserve its integrity.

Common questions

Answers to the questions practitioners most commonly ask about Preservation Master.

Is a preservation master the same as a backup copy?
No. A preservation master and a backup serve different purposes, though the two are often conflated. A backup is typically a routine, operational copy created to enable recovery from data loss or system failure, and it is usually short-lived and overwritten on a cycle. A preservation master is the authoritative, high-quality copy intended to be maintained over the long term as the definitive source from which access or derivative copies are made. Depending on organizational policy, a preservation master is subject to controls aimed at maintaining authenticity, integrity, and usability over time, which ordinary backups are not generally designed to guarantee.
Does keeping a preservation master mean the material is being archived?
Not necessarily. Holding a preservation master concerns the quality and authoritative status of a copy, whereas archiving relates to disposition decisions and the ongoing management of material identified for continued or permanent retention. A preservation master can exist for content that has not yet reached a disposition decision, and disposition itself may include transfer or permanent preservation rather than simply prolonged storage. It is worth keeping the distinction clear: designating a copy as the preservation master describes its role, not the retention or disposition outcome, which depends on organizational policy and applicable requirements.
How should a preservation master be distinguished from access and derivative copies in practice?
Many organizations maintain the preservation master as the untouched, highest-quality authoritative copy and generate separate access or derivative copies for day-to-day use, distribution, or format conversion. In practice this often involves clearly labelling or logically separating the master, restricting routine access to it, and documenting the relationship between the master and any copies derived from it. The specific approach depends on the systems in use and organizational policy, but the underlying aim is typically to protect the integrity of the master while allowing use through copies.
What controls help maintain the authenticity and integrity of a preservation master over time?
Common controls include restricting who can alter or delete the master, capturing and retaining metadata that supports authenticity and provenance, and applying integrity checks so that unintended changes can be detected. Depending on the environment, organizations may also document the chain of custody and any actions taken on the master. These measures support the properties that make something an authoritative record, but the precise combination of controls should be determined by organizational policy, risk assessment, and any applicable requirements.
When is a preservation master typically created in the lifecycle?
This depends on organizational policy and the nature of the material, but a preservation master is often established at or shortly after capture, when the authoritative version of the content can be fixed and its integrity secured before it is used or copied. Establishing the master early can reduce the risk that later handling introduces uncertainty about which version is authoritative. Some workflows may defer designation until a stable, final version exists rather than treating drafts or transitory material as masters.
How does format choice affect the long-term viability of a preservation master?
Format choice can influence how usable a preservation master remains over time, since the ability to render or interpret content depends on continued support for the format and its dependencies. Many preservation programs consider factors such as format stability, openness, and the availability of supporting tools when deciding how to hold the master, and some plan for future format migration while preserving the integrity and documented provenance of the material. The appropriate strategy varies by organization, content type, and available resources, so specific format decisions should be guided by policy and preservation planning rather than a single fixed rule.

Common misconceptions

A preservation master is the same as a backup.
Backups are typically operational copies intended for short-term recovery and business continuity, and may be overwritten on a rotation. A preservation master is retained as an authoritative object for long-term keeping, with fixity monitoring and preservation metadata that support ongoing authenticity and usability. The two serve different purposes and should not be treated as interchangeable.
Creating a preservation master means the object has been archived and no further action is required.
Retaining a master is one step, not the whole of digital preservation. Objects often require active management over time, such as fixity checking and, depending on policy, format migration or emulation, to remain accessible and trustworthy. Simply storing a file does not guarantee its long-term preservation.
The preservation master and the access copy are one and the same file.
In many workflows the master is deliberately kept separate from access or service copies. The master is typically higher fidelity and protected from routine use, while derivatives are optimized for delivery. Conflating the two risks degrading or altering the authoritative version through everyday handling.

Best practices

Generate and record fixity values (such as checksums) when a preservation master is created, and verify them on a scheduled basis to detect corruption or unauthorized change.
Keep the preservation master separate from access, service, and working copies, and restrict routine access to protect the integrity of the authoritative version.
Capture and maintain preservation metadata, including provenance and technical characteristics, so the authenticity, reliability, and usability of the master can be demonstrated over time.
Define preferred preservation formats and derivative-generation workflows in documented organizational policy rather than treating each object case by case.
Plan for active preservation over the retained life of the object, including format migration or emulation as appropriate, rather than assuming that storage alone ensures long-term access.
Align retention and disposition of preservation masters with the organization's records schedule and applicable requirements, recognizing that these depend on jurisdiction and sector.