Melbourne's Duplicate Image Problem: How the City Stacks Up Against Amsterdam, Seoul and Toronto

The City of Melbourne holds more than 340,000 digitised records in its public collections, and a growing share of them are duplicates — the same photograph catalogued twice, sometimes under conflicting metadata, sometimes attributed to the wrong decade or street entirely. The problem is not unique to Melbourne, but how the city handles it is increasingly a point of comparison among archivists and digital-collections managers worldwide.

The issue has sharpened because of a confluence of pressures arriving at once. Pandemic-era digitisation grants, including the Victorian government's Creative Victoria funding rounds from 2021 and 2022, pushed institutions to scan rapidly and upload fast. Speed created noise. Collections that took decades to build physically were added to online systems in months, and quality control did not always keep pace. Now, in mid-2026, the bill is coming due in the form of duplicated assets cluttering search results, inflating storage costs and, in some cases, surfacing incorrect historical information to the public.

Where Melbourne Sits in the Global Picture

Amsterdam's Rijksmuseum resolved a comparable problem between 2019 and 2023 by deploying perceptual hashing — an algorithmic technique that generates a compact fingerprint for each image and flags near-identical copies for human review. The museum publicly reported reducing its online duplicate rate from roughly 12 percent to under two percent across its 700,000-item digital collection. Seoul's National Museum of Korea took a different route, contracting a domestic AI vendor in 2022 to cross-reference its holdings against a national heritage image register, bringing duplicates across four partner institutions down to a manageable queue within eighteen months.

Melbourne's State Library Victoria, housed on Swanston Street in the CBD, began piloting a deduplication workflow in late 2024 using open-source tools adapted from the GLAM (galleries, libraries, archives, museums) sector. The library has not published completion figures, but staff presentations at the Australian Society of Archivists conference in Adelaide in October 2025 described the pilot as covering the photographic collections first, given the volume of near-identical prints that arrived via multiple donor streams. The library's Newspaper and Family History Reading Room on La Trobe Street has separately flagged the challenge of duplicated microfilm scans entering the same digital repository from different digitisation contractors.

The Museum of Melbourne — the rebranded iteration of the former Melbourne Museum network operating out of Carlton — is understood to be at an earlier stage, having only recently consolidated legacy databases from the old collections management system into a unified platform. Digital collections staff there face the additional complication that images acquired through community partnerships with organisations in Footscray and Dandenong sometimes carry overlapping rights metadata, making automated deletion risky even when the image content is identical.

The Cost of Getting It Wrong

Storage is not cheap. Cloud archival pricing for cultural institutions in Australia typically runs between $0.004 and $0.023 per gigabyte per month depending on access tier, and high-resolution master image files average several hundred megabytes each. A collection carrying even five percent duplication across tens of thousands of high-resolution items represents a material ongoing cost — and that is before factoring in the staff hours spent fielding researcher queries generated by conflicting catalogue entries.

Toronto's Toronto Public Library completed a system-wide deduplication audit across its digital branch collections in early 2025, reducing catalogued image assets by approximately 8,400 items and saving an estimated CAD $60,000 annually in storage and licensing overhead. The methodology — a two-stage process combining automated flagging with mandatory human sign-off before any deletion — is now being cited by archivists in other Commonwealth cities as a model worth replicating.

For Melbourne institutions still mid-process, the practical path forward involves prioritising photographic and map collections, which carry the highest duplication risk because of their volume and the multiple contractor streams through which they entered digital systems. Institutions should document their deduplication methodology publicly, both for accountability and to allow peer review from the wider GLAM sector. Researchers using State Library Victoria's catalogue or the Public Record Office Victoria's online holdings at North Melbourne should flag suspected duplicates directly through collection feedback forms — that user reporting, archivists have consistently noted at sector conferences, remains one of the fastest ways to surface errors that automated tools miss.