Digital preservation cannot keep every property of every object forever. The difficult work is deciding which losses would make the preserved object no longer meaningfully the same object for its intended future use.
Convert a document from one format to another and fonts may change. Migrate a spreadsheet and macros may fail. Preserve a video game as a screen recording and the audiovisual appearance survives while interactivity disappears. Export a database to CSV and the rows survive while relationships, constraints and stored procedures can vanish.
Significant properties are the characteristics a preservation programme identifies as important enough that they should survive preservation action to an acceptable degree. Those properties may concern content, structure, appearance, behaviour, context, interaction, precision or evidence.
This article sits beneath How Representational Invariance Works, How Library Preservation Works and How Representation Information Works. The narrow preservation question is: when the form changes, what must not be allowed to change beyond the accepted threshold?
1. “Significant” Depends on Purpose
A property is not significant merely because it exists.
For a legal record, exact textual content, signatures, ordering and provenance may dominate. For a digital artwork, interaction, timing and visual presentation may be inseparable from meaning. For a scientific dataset, numerical precision, units, variable relationships and provenance can matter more than screen appearance.
Significance is therefore tied to the object’s function, evidential role, designated community and preservation intent.
2. Content, Structure, Appearance and Behaviour Are Different Layers
Preservation decisions become clearer when properties are separated.
- Content: words, images, numbers, audio samples, data values.
- Structure: sequence, hierarchy, table relationships, page order, hyperlinks, database relations.
- Appearance: typography, layout, colour, spacing, rendering.
- Behaviour: interaction, formulas, macros, animation, user response, executable logic.
- Context: provenance, dependencies, environment, rights, version state.
A migration can preserve one layer and damage another. Testing needs to match the properties the programme actually cares about.
3. PREMIS Can Record Significant Properties
The PREMIS Data Dictionary includes a semantic unit for significant properties associated with preservation objects. See the current PREMIS Preservation Metadata Maintenance Activity.
The important point is not simply that a field exists. The repository still has to make and justify the preservation decision that gives the field meaning.
4. Significant Properties Are Not Universal Checklists
It is tempting to create one master list: preserve colour, layout, resolution, metadata, interactivity and so on.
That can become misleading because the importance of each characteristic depends on the object type and intended use. A black-and-white legal scan may not need colour fidelity. A colour-managed artwork absolutely may.
Preservation needs explicit local reasoning rather than generic completeness theatre.
5. The Source Object Is the Reference State
Before transforming an object, the preservation team needs to characterise the source.
What fonts are embedded? Which formulas exist? Does the file contain comments, hidden sheets or macros? What colour profile is present? Are there external dependencies? Which hyperlinks resolve? Which interactions are possible?
You cannot test preservation success for a property that was never identified in the source.
6. Preservation Can Be Property-Specific Rather Than Format-Specific
“Convert DOCX to PDF/A” is a format instruction.
“Preserve text, reading order, page-level visual structure, embedded images and searchable Unicode content while macros are intentionally not retained” is a preservation requirement.
The second statement is stronger because it makes the accepted invariants and accepted losses visible.
7. Transformation Information Properties Add a Related OAIS Lens
The current OAIS reference model discusses transformational information properties in the context of preserving information through transformation. That is closely related to the practical significant-properties problem: which information properties must remain preserved across transformation so authenticity and usability claims remain defensible?
8. Significant Properties Can Conflict
Preserving one property can make another harder.
An interactive object can be easiest to keep usable through emulation, while a migration to a modern format may improve broad accessibility but alter behaviour. A high-fidelity image master can preserve colour and detail while being too large for ordinary access.
This is why archives often preserve a high-fidelity source alongside derived access representations rather than forcing one file to perform every job.
9. Significant Properties Need Testable Acceptance Criteria
“Preserve layout” is vague. “No page break may move across a section boundary; headings and figures must retain reading order; all text must remain recoverable” is testable.
Good preservation requirements turn qualitative significance into enough operational detail that migration or emulation can be evaluated consistently.
10. Human Review Still Matters
Automated tools can compare file structure, image dimensions, text extraction, checksums and metadata. They cannot always judge whether an interactive artwork still feels meaningfully the same or whether a document’s visual hierarchy remains intelligible.
Some preservation properties remain partly interpretive and need expert or user evaluation.
11. Worked Example: Spreadsheet
A spreadsheet contains values, formulas, charts, comments, hidden sheets and macros.
If the preservation purpose is evidential reconstruction of the calculation, formulas and dependencies are significant. A flat PDF of the visible sheet preserves appearance and loses the computational model.
If the purpose is simply to preserve the signed final statement that was printed and distributed, the visual rendering may matter more than recalculation.
12. Worked Example: Photograph
For a preservation master, pixel dimensions, bit depth, colour profile, tonal range and embedded technical metadata may be important. For a small web access copy, some of those properties can be reduced intentionally.
The object has not one universal preservation representation, but a preservation strategy with different roles.
13. Worked Example: Video Game
A screen recording preserves visual and audio evidence of play. It does not preserve player agency, rule execution or variable game state.
If interactivity is significant, the preservation strategy may need original executable files, environment documentation and emulation.
14. Worked Example: Database
Exporting tables to CSV can preserve row values and lose referential constraints, indexes, stored procedures, triggers and relationships.
A repository preserving the database as evidence of an operational system may need schema and relationship structure in addition to raw values.
15. Worked Example: eduKate Article Edition
A long-form eduKate article has visible prose, heading structure, links, citation relationships, metadata, canonical ownership and edition identity.
A plain-text export preserves words and loses much of the information architecture. A preservation plan should decide which of those layers matter to future reconstruction before choosing the export or migration path.
16. Failure Mode: Preserving Appearance and Losing Function
A screenshot of a dynamic dashboard can look perfect and preserve none of the queryable data or interactive controls.
Visual similarity is not enough when function is significant.
17. Failure Mode: Preserving Function and Losing Evidence
A recreated application can behave similarly while using reconstructed assets or altered code. If provenance and original state are not preserved, the experience may be usable and evidentially weak.
18. A Significant-Properties Checklist
- Define the object and preservation purpose.
- Identify the designated community.
- Separate content, structure, appearance, behaviour and context.
- Characterise the source before transformation.
- State which properties must survive and why.
- State which losses are acceptable.
- Turn significant properties into testable acceptance criteria where possible.
- Use automated and human validation appropriate to the property.
- Preserve the original when policy and rights allow, especially where future needs may change.
- Record preservation decisions and validation outcomes in preservation metadata.
19. Read the Mechanism Forward, Backward and Sideways
Forward: source object → preservation purpose → significant properties → chosen action → validation → accepted preserved representation. Backward: start from a transformed object that feels wrong and identify which important property was lost. Sideways: compare archivist, creator, domain expert, user and engineer. They may value different properties of the same object, and preservation has to reconcile those claims explicitly.
20. The Civilisation Lesson
Preservation is not the refusal to let anything change. Digital systems make that impossible over long enough timescales.
The mature question is more precise: which characteristics carry the identity, evidence, meaning or capability we are trying to hand forward?
Significant properties are the preservation contract between change and continuity: the explicit statement of what the future is not allowed to lose.
Continue through How Representational Invariance Works, How Representation Information Works and the How X Works hub. Next: archival information packages — how content, context and preservation evidence are organised into a durable archival unit.