Zurich's Digital Archives Face a Reckoning Over Duplicate Images: What Officials and Experts Are Saying

The problem is unglamorous but expensive. Zurich's public institutions, from the Stadtarchiv on Alfred-Escher-Strasse to the cantonal records offices in Oerlikon, are sitting on digital image libraries riddled with duplicate files — redundant photographs, scanned documents and graphics that consume server capacity, inflate licensing costs and slow down archival retrieval systems. Now, a coalition of records managers, IT procurement officers and digital preservation specialists is pushing for coordinated action before the next round of municipal budget decisions in autumn 2026.

The timing is not accidental. Since the UBS absorption of Credit Suisse completed its integration phase, several Zurich-based financial institutions have been rationalising their document management infrastructure, surfacing just how acute the duplication problem has become across the city's institutional sector. Meanwhile, ETH Zurich's Information Science group has been developing open-source deduplication tools as part of its broader digital humanities research agenda, giving local administrators a potential Swiss-built solution to evaluate.

A City-Wide Problem With No Single Owner

Estimates from data management professionals working with Zurich municipal departments suggest that duplicate image files can account for between 20 and 40 percent of total storage in large-scale institutional image repositories — though the precise figure varies sharply depending on how aggressively an organisation has previously managed its digital assets. For institutions running their own on-premise server infrastructure in the city, that represents a direct cost in hardware, cooling and maintenance rather than an abstraction.

The Zentralbibliothek Zürich, which holds one of the most significant digitised image collections in the German-speaking world, has been working since at least 2024 on a programme to clean its digital stacks ahead of a planned public-access portal expansion. Staff there have described the deduplication challenge as more labour-intensive than initially anticipated, particularly when dealing with images that are near-duplicates — slight crops or colour-corrected versions of the same source photograph — rather than exact byte-for-byte copies that automated tools can flag more cleanly.

At the city's media and communications departments, the pressure comes from a different direction. Several Zurich Stadtverwaltung units produce large volumes of event photography each year — documenting everything from Gemeinderats sessions to public festivals along the Limmatquai — and without consistent file-naming and ingestion protocols, the same image routinely enters the system multiple times across different departmental drives.

What Specialists Are Recommending

Digital preservation consultants advising Swiss public institutions have coalesced around several practical recommendations. First, institutions should establish a single canonical image repository with strict ingestion controls rather than allowing individual departments to maintain parallel libraries. Second, any deduplication exercise should distinguish between technical duplicates and intentional versioning — deleting a legitimately revised image because it shares a parent file is a different error from removing a true redundancy. Third, staff training matters as much as software: the tools exist, but without protocol enforcement at the point of upload, the problem regenerates within months.

ETH Zurich's involvement adds an academic dimension that some city administrators find useful as political cover for what is otherwise a difficult internal conversation about IT governance. A research partnership announced in spring 2026 between ETH's Data Management group and two cantonal departments is expected to produce a published framework by the end of the year, giving other Zurich institutions a reference standard to cite in internal procurement discussions.

The practical stakes are sharpest for institutions facing imminent infrastructure decisions. Zurich's ongoing Wohnungsnot crisis has pushed municipal IT spending into competition with housing-related programmes for limited budget space, meaning that storage inefficiency is no longer a problem administrators can defer indefinitely. For those managing Zurich's public image archives, the question of when to act is fast becoming less optional than it once seemed. The city's next round of departmental budget submissions is due in October 2026, and records managers say that proposals without a clear data rationalisation component are likely to face harder scrutiny than in previous cycles.