Barcelona's Digital Archives Push Forward on Duplicate Image Replacement This Week

Barcelona's main municipal digital archive, the Arxiu Municipal de Barcelona, confirmed this week that a coordinated sweep of duplicate image files across its online collections is now actively under way, with a preliminary phase targeting roughly 14,000 redundant entries identified across the city's heritage photography database. The work, which began in earnest on Monday, June 30, follows months of preparatory cataloguing by archivists at the Arxiu Fotogràfic de Barcelona on Plaça de Pons i Clerch in the Sant Pere neighbourhood.

The push matters now because the city faces a September 15 internal compliance deadline tied to its broader Smart City data governance framework, a programme that has been running since 2023 and which links municipal data quality standards to EU digital infrastructure funding criteria. Duplicate and misattributed images are not a minor housekeeping issue: they create errors in public-facing heritage portals, skew search results in educational tools used by schools across the Eixample and Gràcia districts, and in some cases have led to incorrect historical attributions being published on the city's tourism platforms.

The Consorci de Serveis Universitaris de Catalunya, which manages shared digital infrastructure for Catalan universities including the Universitat de Barcelona and the Universitat Pompeu Fabra on Carrer de la Ramona Trias Fargas, is running a parallel deduplication exercise on its own image repositories. That effort specifically targets collections ingested between 2018 and 2022, a period when several digitisation grants led to rapid but inconsistently tagged uploads.

What the Clean-Up Actually Involves

Technical teams are using perceptual hashing software to compare image files at scale, flagging pairs or clusters of visually identical or near-identical photographs that were uploaded under different filenames or metadata entries. A single digitisation campaign of the Poblenou industrial heritage collection, completed in 2021, produced more than 800 confirmed duplicate pairs, according to internal project documentation reviewed as part of this week's announcement. Each flagged pair requires human review before deletion, a step archivists say is non-negotiable for collections with legal or provenance significance.

The practical stakes extend beyond archival tidiness. Barcelona's short-term rental crackdown and associated neighbourhood documentation efforts have generated thousands of property images that feed into licensing databases managed by the Ajuntament de Barcelona's Habitatge department. Duplicate entries in those systems have, in at least some cases, complicated cross-referencing between licence applications and inspection records in dense neighbourhoods like the Barceloneta and the Gothic Quarter, where enforcement pressure has been highest since Mayor Jaume Collboni's administration tightened rental regulations in 2024.

The Museu Nacional d'Art de Catalunya on Montjuïc, which digitised a significant portion of its photographic study collection between 2019 and 2023 under a collaboration with the Getty Foundation, is also participating in this week's coordinated review. Staff there are working through a subset of approximately 3,200 images flagged by automated tools in May, with manual verification expected to conclude before the end of July.

What Happens Next

All participating institutions are expected to submit deduplication reports to the city's Direcció de Serveis d'Arxius i Gestió de Documents by September 1, two weeks ahead of the audit. Where duplicate replacement involves substituting a lower-quality scan for a higher-resolution version under the same catalogue reference, archivists are required to log the change with a timestamped record and a reason code — a protocol introduced after a 2023 review found inconsistent practices across departments.

For researchers, journalists and educators who regularly access the city's open heritage portals, the immediate practical advice is to note reference numbers for any images currently in use, since some catalogue identifiers will change as part of the clean-up. The Arxiu Fotogràfic has posted a notice on its website indicating that affected collections will display a temporary flag during the review period. The full updated catalogue is expected to be publicly accessible in its revised form from October 2026.