Barcelona Tackles Duplicate Images in Its Digital Archives — and Lags Behind Amsterdam and Seoul

Barcelona's municipal archives and cultural institutions are sitting on a significant problem: tens of thousands of duplicate digital images scattered across incompatible databases, accumulated over more than two decades of digitisation drives. The Arxiu Municipal de Barcelona, which holds records dating back to the 13th century, confirmed earlier this year that its ongoing digital consolidation programme — running since 2023 — has identified duplication as one of the primary obstacles to making collections fully searchable and accessible to the public.

The issue matters now because Barcelona is in the middle of an ambitious push to monetise and share its cultural data. Mayor Jaume Collboni's administration has tied digital heritage access to the city's broader creative economy strategy, and duplicate images clog storage, inflate licensing costs, and make it harder for developers building apps and tools on top of open city data. With the tourist tax expansion generating additional municipal revenue earmarked partly for cultural infrastructure, the pressure to show tangible results is real.

What Barcelona Is Actually Doing

The main effort sits inside the Institut de Cultura de Barcelona, known as ICUB, which oversees institutions from the Museu Picasso in Montcada street to the CCCB in the Raval neighbourhood. ICUB launched a metadata harmonisation pilot in early 2025, targeting around 180,000 image records held across five separate content management systems. The pilot uses perceptual hashing — a technique that compares image fingerprints rather than file names — to flag near-identical files for human review before deletion.

Progress has been slow. Conservators at the Arxiu Fotogràfic de Barcelona, based in the Plaça de Pons i Clerch in the Born district, have raised concerns internally about automated removal of images that appear identical but carry different provenance metadata — a particular risk with historical photography where two scans of the same physical print can represent different conservation states. That professional caution is legitimate, but it has meant the deduplication queue is growing faster than it is being cleared.

Barcelona's short-term rental crackdown, which has kept city hall deep in political controversy throughout 2025 and 2026, offers an instructive parallel. The municipal register of tourist apartments took years to cross-reference against actual Airbnb listings, largely because the underlying data lived in incompatible formats across multiple departments. Digital image deduplication faces exactly the same structural problem.

How Barcelona Compares to Amsterdam and Seoul

Amsterdam's Stadsarchief completed a city-wide image deduplication exercise across its entire 750,000-item digital photo collection in 2022, finishing roughly three years ahead of where Barcelona currently stands. The Dutch institution used a centralised asset management platform adopted municipality-wide, which meant a single deduplication pass rather than the institution-by-institution approach Barcelona is taking. Amsterdam also made its deduplicated collection available under a Creative Commons licence almost immediately after the exercise finished, attracting developer interest and press coverage that generated measurable tourism and academic traffic to the archive's web portal.

Seoul's city archive, which digitised aggressively between 2018 and 2023, went further by integrating AI-assisted duplicate detection directly into the upload workflow — meaning new duplicates are flagged before they enter the system. The Seoul Metropolitan Archives reported in March 2025 that this had cut storage costs for new digital acquisitions by roughly 22 percent compared to the 2019 baseline, according to a presentation published by the International Council on Archives. Barcelona has no equivalent gate at the point of ingest yet.

Lisbon is a more flattering comparison. The Arquivo Municipal de Lisboa only began systematic digital deduplication in late 2024, meaning Barcelona is not uniquely behind among Southern European capitals. But Lisbon adopted a unified platform from the start, which analysts expect will allow it to move faster through the backlog once the initial setup is complete.

For Barcelonins who use the city's digital collections — researchers at the Universitat de Barcelona, local historians, or journalists pulling archival photographs — the practical advice is straightforward: when searching the Arxiu Municipal's online portal, cross-reference any image you intend to reproduce against the ICUB catalogue, because the same file often appears under different identifiers and licensing terms in each database. That duplication is exactly what the city is trying to fix. Based on ICUB's current timeline, the pilot phase is scheduled to conclude by the end of 2026, at which point city hall will decide whether to roll the programme out across all municipal collections or pause for further review.