Zurich's Digital Archive Reckoning: What Happens Next and the Key Decisions Ahead

Thousands of duplicate photographs and digitised images sitting across Zurich's public archives are costing the city money it cannot easily justify. Stadt Zürich's digital infrastructure review, ongoing since early 2026, has identified significant redundancy in holdings spread across the Stadtarchiv on Alfred-Escher-Strasse, the Zentralbibliothek Zürich near the Helmhaus, and several smaller municipal collections — and now officials must decide what to do about it before next year's budget cycle closes in October.

The timing matters. Switzerland's federal digitisation push, anchored partly in guidance from Memoriav, the national association for audiovisual heritage, has pushed cantonal and municipal bodies to consolidate collections rather than let parallel digitisation projects sprawl. For Zurich, a city that has spent more than CHF 12 million on archival digitisation since 2019 across various programs, the discovery of large-scale image duplication is not just a housekeeping problem. It is a governance question about who controls the master record, who pays for storage, and whether the public gets any better access as a result of the clean-up.

The Scope of the Problem

Duplicate images in digital archives emerge for straightforward reasons: different departments scan the same physical originals independently, donated collections arrive already partly digitised, and metadata standards shift between projects, making automated deduplication unreliable. Zurich is not unique here. The Schweizerisches Nationalmuseum, headquartered at the Landesmuseum just north of the Hauptbahnhof, has publicly acknowledged wrestling with similar consolidation challenges across its distributed holdings in recent years.

What makes Zurich's situation distinct is scale and urgency. The Stadtarchiv alone holds an estimated 1.2 million digitised items, a figure the city's own documentation references in its 2025 annual report on collections. If duplication rates match those found in comparable European municipal archives — typically running between 8 and 15 percent of total holdings, according to research published by the European Commission's digital cultural heritage working groups — the city could be storing and maintaining anywhere from 96,000 to 180,000 redundant image files. At current cloud-storage and metadata-management contract rates, that is not a trivial overhead.

Three institutions are now at the centre of discussions: the Stadtarchiv itself, the Zentralbibliothek, which holds the cantonal mandate for certain heritage collections, and the Fotoarchiv of Zurich Tourism, whose historical photographic holdings overlap partly with municipal records of the Altstadt and Zürichberg districts. Each operates under different legal frameworks for access and data retention, which complicates any simple merge-and-delete solution.

What Comes Next

The Stadt Zürich Präsidialdepartement, which oversees cultural affairs, is expected to commission a formal deduplication audit by September 2026. That process will likely use fingerprinting software — tools that compare pixel-level hashes rather than file names — to identify true duplicates versus near-duplicates where different scans of the same photograph exist at different resolutions or crop ratios. The latter category raises harder questions: which version is authoritative, and who decides?

For institutions like the Zentralbibliothek, the practical consequence could mean transferring certain holdings back to the Stadtarchiv as the single canonical repository, ending a duplication that was partly the result of post-merger arrangements following administrative restructuring in 2021. Any such transfer requires sign-off from the Kantonsrat, Zurich's cantonal parliament, if cantonal collections are involved — adding a political layer to what might look like a technical exercise.

Public access is the variable that archivists say will determine whether this exercise has any meaning beyond cost-cutting. Researchers working out of ETH Zürich's history of science department, which regularly draws on city image archives for urban development studies, have long pressed for a unified search portal rather than three separate query systems. A deduplication process done well could finally make that possible. Done poorly — or simply used to justify storage cuts without improving metadata — it will leave the collections harder to use than before.

The October budget deadline is the first hard checkpoint. If the Präsidialdepartement does not secure provisional funding for the audit and a follow-on consolidation phase by then, the decision effectively defers to 2027 — by which point further digitisation projects currently in planning for the Landesmuseum partnership will have added more records to an already unwieldy system.