# Duplicate review

[← Documentation index](../index.md) · [Guided first pass](../first-pass.md)

![The duplicate cluster list](../images/duplicates.png)

**What it is for.** Deciding which file is *the* copy of a picture, before anything
expensive or irreversible happens to the others.

**What you decide.** For each cluster: keep the recommended canonical, choose a
different one, keep everything as variants, declare it not a duplicate, or defer.

**What it changes.** Only the decision, recorded as an auditable event. **No file is
ever deleted.** Non-canonical copies stay exactly where they are; they are simply
excluded from analysis and upload.

**What it refuses.** Exact byte and identical-pixel matches may be accepted on the
recommendation. Anything fuzzy — a crop, a re-encode, a burst frame — requires an
explicit confirmation, because a perceptual hash is evidence, not proof.

## Reading a cluster

Each member shows its path, role, pHash distance, and size, with synchronised zoom
across the previews. The recommendation is visible but never pre-applied for fuzzy
matches. The confidence band tells you how much the machine is claiming.

Rejecting a pair records a negative link, so a later rescan does not keep proposing
the same wrong match.

## Why first

Resolving duplicates before safety and analysis is what stops you reviewing and
paying for the same photograph three times. It also means the album evidence is built
from one copy of each picture rather than a skewed count.

Next: [safety review](safety.md).