Metadata
The problem in one line
Paris, paris, Paris, France, PARIS 11e, Paris (FR). To you, one place. To your catalog, five distinct values — so five search facets, five partial result sets, and one image in five missing from the count.
Normalization means reducing those variants to a single reference value while keeping a record of what was originally written.
Where the spread comes from
- Successive imports, made at different times under different conventions.
- Tools passed through: each writes the same notions into slightly different fields.
- Multiple hands: two people never type a proper noun the same way.
- Free-text entry, which permits every spelling and suggests none.
An older collection accumulates all four. That’s normal, and harmless — provided you address it before the volume makes the cleanup discouraging.
What normalization actually covers
- Case and whitespace: the easiest, and already a good share of the noise.
- Spelling variants of one entity, reduced to a preferred form.
- Synonyms, linked so that searching one finds the other.
- Equivalent fields from different tools, aligned onto a target field.
- Disguised empties:
n/a,unknown,-,tbd, which pollute facets by posing as data.
The rule that prevents damage
Normalizing doesn’t mean overwriting. The original value is information: it documents what was written, by whom, and when. A heritage collection needs that.
So keep the preferred form and the entered form. An alias pointing at a reference value fixes retrieval without destroying the record.
In practice
- Start by measuring: list the distinct values of a field, sorted by frequency. The tail of that list is your work.
- Handle case and whitespace first — immediate, risk-free gains.
- Build a vocabulary of preferred forms, using aliases rather than destructive replacements.
- Eliminate disguised empties.
- Add validation at entry, or the spread returns from the top.
Obscura Flow supports synonyms and aliases so several spellings point at the same entity, and preserves metadata blocks read at import verbatim — the original form stays readable after normalization.