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Nov 13, 2026

Normalization on ingest (preservation masters)

Audience: archivist, digital preservation officer, sysadmin

Normalization creates an open, long-lived "preservation master" copy of an ingested file - the way Archivematica does. For example a JPEG becomes a TIFF, a Word document or PDF becomes PDF/A, an MP3 becomes WAV, and a proprietary video becomes a Matroska/FFV1 file. The original is always kept; the master is an additional, format-stable copy held against the day the original format becomes hard to open.

Turning it on

Normalization is opt-in (it is heavier and more opinionated than the always-on baseline of checksum + format-ID + virus + PREMIS):

  • On the Data Ingest Configure step, tick "Normalize (preservation master)".
  • When the ingest commits, each created digital object is queued for normalization (it runs in the background so large ingests are not held up).

What you get per object

  • A preservation master file in the target open format, attached to the record as a linked digital object with usage "Preservation Master".
  • A fixity checksum on the master.
  • A PREMIS normalization event recording the source, the target format and the tool used.
  • A row in the format-conversion log (source/target, sizes, checksums, duration).

Preservation masters and access copies

Two kinds of copy are produced, each driven by its own rules:

  • Preservation master - an archival, lossless/open format (image -> TIFF, office/PDF -> PDF/A, audio -> WAV, video -> Matroska/FFV1). Attached with usage "Preservation Master".
  • Access copy - a web-friendly format for delivery (TIFF/PNG -> JPEG, office -> PDF, WAV -> MP3, Matroska -> MP4). Attached with usage "Reference".

When you tick Normalize on ingest, both are produced where a rule matches.

What controls the target format

A rule registry - the format policy registry - maps each source format to its target and tool. Manage it at Preservation -> Normalization Rules (add/edit/toggle/delete rules; separate rules for the preservation and access purposes). Defaults cover common image, office/PDF, audio and video formats. A file with no matching rule (or already in the target format, e.g. a TIFF for the preservation purpose) is simply left as-is.

Normalizing files that are already in the catalogue

To backfill masters/access copies for objects ingested before normalization was enabled, run:

php artisan ahg:normalize-existing --purpose=preservation   # or --purpose=access

Options: --limit=N, --mime=image/jpeg, --sync (run inline instead of queueing).

Where to see it

  • Central Dashboard → Data Ingest card: a "normalized" count appears next to the preservation figures once masters exist.
  • Preservation dashboard → conversions / events: the normalization events and conversion records.
  • The record's digital-object panel: the Preservation Master derivative.

Requirements

  • The conversion tools must be installed on the server: ImageMagick (images), Ghostscript (PDF/A), FFmpeg (audio/video), LibreOffice (office documents).
  • The Digital Preservation module must be installed. If a tool or the module is missing, normalization is skipped and the ingest still completes - the failure is logged, never fatal.
  • Automatic digital preservation on ingest (the always-on baseline)
  • PREMIS XML export
  • Preservation packages (BagIt / AIP)