Zurich's Digital Archives Are Full of Duplicate Images — Officials and Experts Are Tired of Waiting for a Fix

Zurich's public institutions are sitting on millions of duplicate digital images — photographs, scans, and architectural renderings filed multiple times across overlapping databases — and the city's archivists, IT planners, and academic librarians say the problem has reached a breaking point. Estimates circulating among cantonal records officers suggest that between 15 and 30 percent of all image files stored in public digital repositories are redundant duplicates, a figure that has drawn sharp criticism from budget-watchers on the Gemeinderat.

The issue has moved from a technical irritant to a genuine fiscal concern at a moment when Zurich's public finances are under close scrutiny. The canton is still managing the downstream effects of the UBS-Credit Suisse consolidation, which reshuffled thousands of administrative and back-office roles in the city's Kreis 1 and Kreis 2 financial district. Simultaneously, the Stadtarchiv Zürich — located on Neumarkt — has been expanding its digitisation programme, pulling in analogue material from dozens of city departments, each with its own filing conventions and no unified deduplication protocol.

What the Experts Are Saying

Archivists and digital-records specialists in Zurich have been pointing to the same structural problem for several years: the city's digital infrastructure was built incrementally, department by department, without a central image-management standard. ETH Zürich's Chair of Information Science, based on the Hönggerberg campus, has published research on hash-based image deduplication methods that could theoretically cut redundant storage by more than half in large institutional datasets. That research, widely cited in European library-science circles, has not yet been formally adopted by any Zurich city agency, according to information available in publicly accessible cantonal planning documents.

Practitioners at the Zentralbibliothek Zürich on Zähringerplatz have noted internally — in annual reports made available online — that the volume of incoming digitised material has outpaced the library's ability to cross-check new uploads against existing holdings. The library processed roughly 2.4 million new digital objects in 2024 alone, according to its published annual report, and a significant portion of those objects were image files transferred from partner institutions including the Stadtarchiv and the Kunsthaus Zürich.

Zurich's cantonal IT office, the Amt für Informatik, flagged duplicate-data management as a priority item in its 2025-2028 digital strategy document. The document, published in late 2024 and available on the canton's official website, describes a planned migration to a unified asset-management platform but does not commit to a specific go-live date. Critics on the Gemeinderat's finance committee have pointed out that without a firm timeline, incremental storage costs will continue accumulating — cloud storage alone for cantonal image archives is understood to run into seven-figure annual expenditure, though precise budget line figures have not been publicly broken out.

The Path Forward

Specialists working in the field broadly agree on what a solution looks like: a city-wide digital asset management system with automated perceptual hashing — a technique that identifies visually identical or near-identical images regardless of file name or format — combined with a mandatory metadata standard for any institution transferring files to central cantonal repositories. Several European municipal archives, including those in Vienna and Hamburg, have already implemented comparable systems in the past three years.

For Zurich, the practical next step appears to hinge on a procurement decision expected from the Amt für Informatik before the end of the third quarter of 2026. If that decision is delayed again — it was already postponed once, from a planned Q4 2025 announcement — digital archivists at institutions along Neumarkt and Zähringerplatz say they will face another year of manual triage, a labour-intensive process that pulls skilled staff away from primary conservation work. Zurich residents who interact with the city's digital services — from planning-document portals to the online collections of the Kunsthaus — may not notice the problem directly. The people who catalogue and maintain those records notice it every single day.