Barcelona's City Archive Launches Emergency Audit After Duplicate Images Surface Across Digital Collections

Barcelona's municipal digital archive has a problem. Thousands of photographs held in the Arxiu Municipal de Barcelona — including historic images of the Eixample grid, the 1992 Olympic construction works, and street life along La Rambla — have been identified as duplicates or mislabelled entries within the institution's public-facing online catalogue, according to internal documentation circulated to city council members this week. The discovery has triggered an emergency audit, with archive staff pulling access to roughly 4,200 records while the review proceeds.

The issue surfaced in late June, when technicians running a routine metadata check ahead of a planned catalogue expansion noticed that automated ingestion software had been creating duplicate image entries since at least January 2025. The problem is not unique to Barcelona — digitisation drives across European municipal archives have routinely produced similar catalogue errors — but the scale matters here. The Arxiu Municipal holds more than two million photographic items, and the city has invested heavily in making those collections accessible online as part of its Smart City strategy.

What Went Wrong and Where It Showed Up

The duplicates appear concentrated in two specific collection areas: the Fons Fotogràfic de la Guàrdia Urbana, which documents police and public-order events from the 1960s onwards, and a batch of images donated to the Arxiu Nacional de Catalunya in Carrer dels Almogàvers, Sant Martí, which were subsequently cross-referenced into the municipal system. When the automated ingestion pipeline processed cross-referenced entries, it generated secondary records without flagging them as copies, effectively doubling the visible catalogue count for those collections.

Researchers using the archive's public portal — accessible through the Ajuntament de Barcelona's open-data gateway — began noticing the anomaly earlier this spring. Several academics working at the Universitat Pompeu Fabra's Department of Communication, which uses the archive regularly for urban history projects, had raised informal concerns with archive staff before the formal audit was announced. The city has not yet released a full figure for how many unique images are affected, but the 4,200 restricted records represent less than 0.25 percent of the total digitised holdings, according to figures cited in the council briefing document.

The practical consequences are real, even at that scale. Journalists, urban planners applying for licences in the Gràcia and Poblenou districts, and heritage consultants preparing reports for protected buildings along Passeig de Sant Joan have all encountered broken or duplicated catalogue links in recent weeks. The Arxiu's reading room at Carrer de Santa Llúcia, in the Gothic Quarter, remains open for in-person consultations, and staff there have been handling increased walk-in traffic as researchers work around the online restrictions.

Timeline for Resolution and What Researchers Should Do Now

The Ajuntament has said the audit will run through July 18, after which corrected metadata will be reloaded to the public portal in stages. The fix involves running a deduplication algorithm against the full digitised collection — a process that archivists say will take approximately three weeks of processing time on the city's current infrastructure. A secondary manual review is planned for the most heavily accessed collections, which include materials from the 1986-1992 Olympic preparation period, a set of records in high demand given ongoing academic interest in urban transformation.

For researchers who cannot wait, the Arxiu Nacional de Catalunya's own online system at Carrer dels Almogàvers holds independent copies of the cross-referenced collections and has not been affected by the deduplication issue. The Institut Municipal d'Urbanisme also maintains a separate photographic record relevant to planning history, accessible by appointment at its offices on Avinguda Diagonal.

The episode points to a structural tension in how Barcelona — and cities like it — have accelerated digitisation without always building in the quality-control layers that large-scale automated ingestion requires. The city allocated €1.2 million to archive digitisation in its 2025 municipal budget, a figure that prioritised volume of scanning over metadata verification infrastructure. Whether the audit produces a formal recommendation to revise that balance is now the question archive staff and council members will need to answer before the next digitisation contract is signed.