Preservation events

This page specifies the elements of a preservation event and the event types used in DPS. For what events are and why they matter, see Preservation events. For how to choose and submit events, see Add preservation events.

Event elements

The following elements are permitted:

Agent (agent):*

• agentName*
• agentType*
• agentVersion
• agentNote

Event (top level):

• eventDateTime*
• eventType*
• eventDetail
• fileRef (with relativePath* when fileRef is used)
• outcome*
• outcomeDetail

Elements marked with * are required.

Agent

The Agent describes the actor (who or what) that performed the action. This may be software, an organization, or a person. The information should be sufficiently precise to identify which actor and configuration was used.

AgentName

The name of the actor that performed the action. The name must be unique and used consistently.

Examples:

• “Apache NiFi”
• “Nasjonalbiblioteket – Team Digital Preservation”
• “Ola Nordmann”
• “JHOVE”

AgentType

Specifies the type of actor that performed the action. Values are taken from the Library of Congress vocabulary for agentType.

Allowed values:

• “software”
• “organization”
• “person”
• “hardware”

AgentVersion

The version or revision of the agent. This field is only relevant for software and hardware agents. AgentVersion is used to ensure traceability and reproducibility, as different versions of the same tool may produce different results.

Examples:

• “1.15.0”
• “3.2”
• “1.11.0; DROID_SignatureFile_V116.xml; container-signature-20231127.xml”

AgentNote

Additional information about the agent that performed the action. This element documents characteristics, context, or configuration of the agent itself — not what the agent did in a specific event.

This may include:

• What the agent is and what it does in general.
• How the agent is configured or installed.
• Operational context or responsibility.

Examples:

• “File format identification tool using PRONOM signatures. Installed with signature set v95 for PDF, TIFF, JPEG, and XML formats.”
• “Dataflow automation tool that enables the design and management of complex data pipelines.”
• “Custom installation with PDF, TIFF and JPEG modules enabled. Running under Java 17 runtime environment.”
• “Institution with formal responsibility for digital preservation, ingest, and long-term management of archival materials.”

Event

The Event describes the action performed on the object.

EventDateTime

The date and time when the event occurred. Must be expressed according to the ISO 8601 standard, including time zone.

Example:

• “2026-02-23T10:45:00+01:00”

EventType

Specifies the type of action performed. This element describes the kind of process the event represents. The value must be a controlled and consistently used term — see list of allowed event types below.

EventDetail

A precise description of what was done in the event. The description should indicate which operation was performed, on which object, and where applicable, which method, standard, or process was used.

Examples:

• “MD5 checksum generated.”
• “Migrated from TIFF to JPEG2000.”
• “Validated against PDF/A-2b standard.”

Outcome

The overall result of the event. This element indicates whether the event was completed as expected, failed, or was completed with deviations. The value should be used consistently for equivalent events. Values are taken from the Library of Congress vocabulary for eventOutcome.

Allowed values:

• “success” – the event succeeded in having its intended result.
• “warning” – a warning was generated by the event, indicating that it needs to be evaluated. This also includes partial success, for example a validation reporting a breach of a SHOULD requirement.
• “fail” – the event did not succeed in producing the intended result.

OutcomeDetail

This element is only used when additional information about the outcome needs to be documented. In many cases, it is sufficient to use the “Outcome”-element (success, warning, fail). “OutcomeDetail” is a concrete and precise description of the result of the event. This field should be used when the result contains information relevant for further use, control, or documentation. This element documents what was actually achieved or which deviations were identified. The description should be concise and clear.

Examples:

• “Identified as fmt/353 (TIFF 6.0).”
• “The package was validated against the profiles E-ARK-SIP-v2-2-0, NB-SIP-STRUCTURE-1.0, and NB-SIP-MOVINGIMAGES-PROFILE-1.0, resulting in one warning: CSIPSTR13 the representation folder primary_20250325 is missing the metadata subfolder (SHOULD requirement). Processing continued.”

Event types accepted through the API

The National Library bases its work on the Library of Congress list of EventTypes. This list has been narrowed down, and the use of the different types has been specified to suit our needs and preservation environments. Event types other than those specified in the list below are not approved in the API.

Capture

Guidelines for use:

• Used for capture of websites during crawling functions of a repository.

Example:

{
  "agent": {
    "agentName": "Heritrix Web Crawler",
    "agentType": "software",
    "agentVersion": "3.5.0",
    "agentNote": "Used for web archiving to capture websites; HTML, images, scripts, and linked resources."
  },
  "eventDateTime": "2026-02-03T07:14:01.716+01:00",
  "eventType": "capture",
  "eventDetail": "Captured the website https://example.org; including all pages, images, PDFs, and linked resources, according to the scheduled web archiving crawl.",
  "outcome": "success",
  "outcomeDetail": "Total pages captured: 234; total data size: 1.2 GB; all URLs successfully archived in WARC format."
}

Creation

Guidelines for use:

• Used to document the creation of a digital object.
• Used to document the origin of the file or Intellectual Entity, describes the method and process of creating the file/IE. See also eventType “imaging”.

Example:

{
  "agent": {
    "agentName": "Pyramix",
    "agentType": "software",
    "agentVersion": "15.0.8",
    "agentNote": "Software for recording, editing, mixing, and mastering audio."
  },
  "eventDateTime": "2026-02-03T08:02:17.304+01:00",
  "eventType": "creation",
  "eventDetail": "Digitization of a physical carrier, 1/4-inch audio tape, to WAV/BWF using Pyramix and an A/D converter. Recording performed in real time from an analog source via an external converter. Verified recording quality.",
  "outcome": "success"
}

Filename change

Guidelines for use:

• Used when changing the filename of a digitally created file.
• Documents a complete or partial change to the original filename, for example to remove prohibited characters or spaces, comply with the current filename standard, or correct errors in the filename.

Example:

{
  "agent": {
    "agentName": "Apache NiFi",
    "agentType": "software",
    "agentVersion": "2.4.0",
    "agentNote": "Dataflow automation tool that enables the design and management of complex data pipelines."
  },
  "eventDateTime": "2026-02-03T10:47:29.332+01:00",
  "eventType": "filename change",
  "eventDetail": "The filename was changed from NN_TR_2011_01_31_18_40.mp4 to NRK_TR_2011_01_31_18_40.mp4 to comply with the current filename standard. The filename prefix indicates the radio channel from which the file originates. The original prefix, NN, was incorrect and was replaced with NRK.",
  "fileRef": {
    "relativePath": "representations/primary_20250325/data/NRK_TR_2011_01_31_18_40.mp4"
  },
  "outcome": "success"
}

Fixity check

Guidelines for use:

• Used to verify that a digital object has not been altered by checking and comparing its checksum against a previously recorded checksum.
• The event should be associated with the IE whenever possible. It should only be associated with an individual file when deviations need to be documented.
• Will most likely contain the results of the “message digest calculation” event.
• Particularly important when checksums are received from external sources.

Example:

{
  "agent": {
    "agentName": "md5sum (GNU coreutils)",
    "agentType": "software",
    "agentVersion": "8.32",
    "agentNote": "Tool used to calculate and verify checksums to control data integrity over time."
  },
  "eventDateTime": "2026-02-03T12:05:48.210+01:00",
  "eventType": "fixity check",
  "eventDetail": "MD5 checksums were verified against previously registered values for all files in the package.",
  "outcome": "success"
}

Imaging

Guidelines for use:

• Used to document the process of creating an exact digital copy (disk image) of a storage medium, including all files, metadata, file system structure, and sometimes also free space and deleted data.
• As a general rule, this event should be used instead of the creation event, rather than in addition to it. However, in some cases, it may be relevant to use both events.

Example:

{
  "agent": {
    "agentName": "GNU ddrescue",
    "agentType": "software",
    "agentVersion": "1.27",
    "agentNote": "Tool used to create bit-for-bit disk images from physical storage media."
  },
  "eventDateTime": "2026-02-03T09:00:00+01:00",
  "eventType": "imaging",
  "eventDetail": "Created a bit-for-bit disk image from an external hard drive. The disk image includes the file system structure and associated metadata from the original media.",
  "outcome": "success"
}

Information package creation

Guidelines for use:

• Used when a SIP, AIP or DIP is created as a new information package, including the establishment of package structure, metadata, and associated files in accordance with the applicable packaging standard (e.g. E-ARK).
• Should not be used for simple copying or transfer of existing packages without changes to package structure or metadata.
• If the SIP Generator developed by the National Library is used without modification, use the agent from the first example.

Example:

{
  "agent": {
    "agentName": "nifi-nb-eark-nar.EarkSIPGenerator",
    "agentType": "software",
    "agentVersion": "1.0.11",
    "agentNote": "Apache NiFi processor developed by the National Library for creating E-ARK SIPs. Uses commons-ip, a Java library for the creation and management of E-ARK information packages."
  },
  "eventDateTime": "2026-02-03T16:42:15+01:00",
  "eventType": "information package creation",
  "eventDetail": "Created a SIP in accordance with the National Library's Profile SIP 1.0.",
  "outcome": "success"
}

{
  "agent": {
    "agentName": "org.roda-community:commons-ip2",
    "agentType": "software",
    "agentVersion": "2.12.0",
    "agentNote": "Java library for the creation and management of E-ARK information packages."
  },
  "eventDateTime": "2026-02-03T16:58:03+01:00",
  "eventType": "information package creation",
  "eventDetail": "Creation of an E-ARK SIP in accordance with the E-ARK Common Specification (CSIP) V.2.2.0, E-ARK SIP V.2.2.0, and the National Library of Norway specifications SIP 1.0 (E-ARK).",
  "outcome": "success"
}

Message digest calculation

Guidelines for use:

• Used when generating new checksums. If checksums are generated locally, there is no need to use the “fixity check” event in addition to the “message digest calculation” event. See also EventType “fixity check”.
• The “fixity check” event documents the verification of checksum(s).
• The event should be associated with the IE whenever possible. If deviations need to be documented, they should be associated with the relevant file.

Example:

{
  "agent": {
    "agentName": "md5sum (GNU coreutils)",
    "agentType": "software",
    "agentVersion": "8.32",
    "agentNote": "Tool used to calculate and verify checksums to control data integrity over time."
  },
  "eventDateTime": "2026-02-03T13:36:42.455+01:00",
  "eventType": "message digest calculation",
  "eventDetail": "Calculated MD5 checksum for all the files in the package.",
  "outcome": "success"
}

Metadata extraction

Guidelines for use:

• Used when metadata is extracted from a file.
• The derived metadata must reference the source file in "fileRef".
• If the extraction results in one or more metadata files, "outcomeDetail" must include a reference (relative file path) to the extracted/generated metadata file(s).

Examples:

Example of metadata extraction documented in outcomeDetail:

{
  "agent": {
    "agentName": "ExifTool",
    "agentType": "software",
    "agentVersion": "12.60",
    "agentNote": "Extracts technical metadata from files."
  },
  "eventDateTime": "2026-02-19T11:45:32.123+01:00",
  "eventType": "metadata extraction",
  "eventDetail": "Extracted technical metadata from image file.",
  "fileRef": {
    "relativePath": "representations/rep-images_20230908/data/DSC_0456.JPG"
  },
  "outcome": "success",
  "outcomeDetail": "Image: format JPEG, resolution 8256x5504 pixels, 24-bit color; Camera: Nikon D850; Lens: 24-70mm f/2.8; Exposure: 1/125 sec at f/8; ISO: 100; File size: 18.2 MB."
}

Example of metadata extraction stored as a separate file:

{
  "agent": {
    "agentName": "Audioinspector",
    "agentType": "software",
    "agentVersion": "5.5",
    "agentNote": "A software tool for automated analysis, quality assessment, and metadata management of audio files."
  },
  "eventDateTime": "2026-02-11T12:01:08Z",
  "eventType": "metadata extraction",
  "eventDetail": "The WAV file was analyzed for quality control and documentation.",
  "fileRef": {
    "relativePath": "representations/primary_20250325/data/something.wav"
  },
  "outcome": "success",
  "outcomeDetail": "An XML metadata file was created, containing detailed analysis results: representations/primary_20250325/metadata/technical/audioinspector/metadata.xml"
}

Migration

Guidelines for use:

• Used when one or more files are converted to a different file format.
• The event should be associated with the Intellectual Entity (IE) whenever possible, for example, if the files have been converted in the same way to the same format.
• Migration events should always create a new file(s) or package.
• Relevant parameters describing the migration process should be documented in eventDetail.
• The migrated file(s) must reference the source file in fileRef when single files are migrated (when the event is not associated with IE).
• outcomeDetail must include a reference (relative file path) to the migrated file(s).

Example:

{
  "agent": {
    "agentName": "FFmpeg",
    "agentType": "software",
    "agentVersion": "6.0",
    "agentNote": "Media conversion and encoding of AV files."
  },
  "eventDateTime": "2026-02-03T15:09:55.774+01:00",
  "eventType": "migration",
  "eventDetail": "Batch migration of all MOV files in the package (25 files) to MXF/Op1a format with lossless JPEG2000 video codec and 24-bit PCM audio codec. Parameters used: command=ffmpeg -i input.mov -c:v jpeg2000 -pred dwt53 -c:a pcm_s24le output.mxf; container=MXF/Op1a; videoCodec=JPEG2000 (lossless, dwt53); audioCodec=PCM 24-bit; integrityChecked=yes",
  "outcome": "success",
  "outcomeDetail": "Resulting MXF files stored in representations/primary_20250325/data/."
}

Transfer

Guidelines for use:

• Used for transfer of material between systems or organisational contexts, for example from a producer to a preservation system or between storage environments. Should not be used for internal workflows or internal processing steps.
• Do not use the transfer event for transfer of material into DPS (submission via API), the system automatically creates an event when the material is received.

Example:

{
  "agent": {
    "agentName": "Apache NiFi",
    "agentType": "software",
    "agentVersion": "2.4.0",
    "agentNote": "Dataflow automation tool that enables the design and management of complex data pipelines."
  },
  "eventDateTime": "2026-02-18T14:02:33+01:00",
  "eventType": "transfer",
  "eventDetail": "Transferred package from preservation storage Oracle HSM (SAM-FS) to local workspace for further processing; source checksums were verified with md5sum (GNU coreutils) during upload.",
  "outcome": "success"
}

Validation

Guidelines for use:

• Used when a package or file is checked to verify that it complies with a specific standard, profile, specification, or other defined requirements.
• The object being validated may be an individual file or an Intellectual Entity (IE). Whenever possible, the event should be associated with the IE, for example when multiple files are validated in the same way using the same tool, or when the structure of the package is validated as a whole. The event should also specify what the validation was performed against, such as a standard, profile, specification, or other defined requirements.
• It may be appropriate to create a single event covering the entire validation process, and instead describe which tools are used in the different steps, rather than creating multiple events for multiple validations.

Examples:

{
  "agent": {
    "agentName": "JHOVE",
    "agentType": "software",
    "agentVersion": "1.32.1",
    "agentNote": "Tool used for identification, validation and characterisation of digital objects."
  },
  "eventDateTime": "2026-02-03T17:30:39.662+01:00",
  "eventType": "validation",
  "eventDetail": "Validated all PDF files in the package (35 files) using JHOVE to verify that they comply with the PDF 1.7 specifications.",
  "outcome": "success"
}

{
  "agent": {
    "agentName": "Apache NiFi",
    "agentType": "software",
    "agentVersion": "2.4.0",
    "agentNote": "Dataflow automation tool that enables the design and management of complex data pipelines."
  },
  "eventDateTime": "2026-02-03T17:41:12.508+01:00",
  "eventType": "validation",
  "eventDetail": "Validated E-ARK SIP using DPS Validation workflow v.a00f683: nifi-nb-eark-nar.EarkSIPValidator 1.0.7; org.roda-community:commons-ip2 2.12.0. Validated against profiles E-ARK-SIP-v2-2-0, NB-SIP-STRUCTURE-1.0 and NB-SIP-MOVINGIMAGES-PROFILE-1.0.",
  "outcome": "success"
}

Example of a validation with deviations that did not stop processing:

{
  "agent": {
    "agentName": "Apache NiFi",
    "agentType": "software",
    "agentVersion": "2.4.0",
    "agentNote": "Dataflow automation tool that enables the design and management of complex data pipelines."
  },
  "eventDateTime": "2026-02-03T17:48:05.219+01:00",
  "eventType": "validation",
  "eventDetail": "Validated E-ARK SIP using DPS Validation workflow v.a00f683: nifi-nb-eark-nar.EarkSIPValidator 1.0.7; org.roda-community:commons-ip2 2.12.0.",
  "outcome": "warning",
  "outcomeDetail": "Validated against profiles E-ARK-SIP-v2-2-0 and NB-SIP-STRUCTURE-1.0 with one warning: CSIPSTR13 – the representation folder primary_20250325 has no metadata subfolder (SHOULD requirement). Processing continued."
}

Virus check

Guidelines for use:

• The event should be linked to the IE where possible. Linked to the File only when it is necessary to document discrepancies.
• If a virus or other malicious software is found, outcome must be fail. Link the event to the affected file with fileRef, and describe the finding in outcomeDetail.

Examples:

{
  "agent": {
    "agentName": "ClamAV",
    "agentType": "software",
    "agentVersion": "1.4.2",
    "agentNote": "Antivirus software used to detect malicious software. Virus signatures: daily.cvd, version 27890; main.cvd, version 12345."
  },
  "eventDateTime": "2026-02-03T18:27:53.842+01:00",
  "eventType": "virus check",
  "eventDetail": "All files in the package were scanned for viruses and other malicious software prior to further processing.",
  "outcome": "success"
}

{
  "agent": {
    "agentName": "ClamAV",
    "agentType": "software",
    "agentVersion": "1.4.2",
    "agentNote": "Antivirus software used to detect malicious software. Virus signatures: daily.cvd, version 27890; main.cvd, version 12345."
  },
  "eventDateTime": "2026-02-03T08:51:40.127+01:00",
  "eventType": "virus check",
  "eventDetail": "The file was scanned for viruses and other malicious software prior to transfer.",
  "fileRef": {
    "relativePath": "representations/primary_20250325/data/file_2026.xml"
  },
  "outcome": "fail",
  "outcomeDetail": "Detected the signature Win.Trojan.MacroVirus-12345."
}

Events generated by DPS

DPS records its own events during ingest, during preservation, and when content is retrieved. These include events for transfer, validation, verification, file format identification, and technical metadata extraction. Some of these event types are only used internally and cannot be submitted through the API.