Organization
Why the filename isn’t enough
A filename is an address, not an identity. It changes when you reorganise, when a tool normalises it, when a client renames a deliverable. Every change breaks all external references: the email citing Shoot_042.jpg, the invoice, the licence agreement, the published caption.
An inventory number is an identity. Assigned once, it never changes, whatever the file’s location or name. It’s what lets you talk about an image without knowing where it’s filed.
The five rules of a durable identifier
1. Immutable. Once assigned, never modified. If the image leaves the collection, its number is withdrawn and never reassigned — a burned number beats a number that designates two things depending on the year.
2. Opaque as to content. Don’t encode the subject, the client, or the filing scheme. All of that changes, and you’ll end up with numbers that lie. A date and a counter are enough.
3. Readable and dictatable. It will be read over the phone, copied by hand, printed on the back of a print. Avoid ambiguous characters, spaces, and accents. A fixed length helps spot a typo.
4. Sequential with accepted gaps. A sequence obtained transactionally, whose gaps are never filled. Filling a gap means reusing a number: precisely what’s forbidden.
5. Independent of the software. The number must be written into the file’s metadata, not only into your catalog database. Otherwise it disappears with the tool.
A scheme that works
PREFIX-YEAR-NNNNN: a short prefix for the collection or studio, the year of entry into the inventory, a fixed-width counter. For example AFB-2026-00317.
The year isn’t decorative: it bounds the sequences, avoiding a single counter that reaches seven digits, and it situates the entry in the inventory — without claiming to date the exposure, which is separate information.
For a catalogue raisonné, the work number follows the same logic but designates the work, not the file: several files and several prints can attach to it.
Where to write it
- In the catalog, obviously.
- In the file’s metadata or its sidecar, so it survives losing the catalog.
- In the filename, as a prefix — not as the source of truth, but as convenience: a file found out of context stays identifiable.
- On the physical print, on the back, if one exists.
In practice
- Assign a number on entry, never retroactively.
- Encode nothing in it that might change.
- Never fill a gap in the sequence.
- Write it into the metadata, not only into the database.
- Distinguish the file’s inventory number from the work’s catalogue number.
- Test it: an isolated file, without your software, must stay identifiable.
Obscura Flow assigns durable inventory numbers obtained transactionally, with gaps left unfilled, writes them into file metadata, and maintains immutable catalogue numbering on the work side — identity survives both renaming and a change of tooling.