Zurich's Digital Archives Face a Hidden Crisis: Officials and Experts Warn on Duplicate Image Sprawl

Zurich's public institutions are sitting on a quiet but costly problem. Across municipal servers, university research repositories, and cantonal planning databases, duplicate digital images have accumulated for years — the same photographs, scans, and graphic files stored two, three, sometimes a dozen times across overlapping systems. Experts working in the field say the issue has reached a point where it can no longer be treated as routine housekeeping.

The timing matters. Switzerland's Federal Archives Act, revised in 2023, placed new obligations on cantonal bodies to demonstrate orderly digital records management by January 2027. Zurich, as the country's most populous canton, faces the steepest compliance burden. The city's Stadtarchiv on Neumarkt and the cantonal administration at the Walcheturm complex both confirmed in written communications this spring that internal audits were underway, though neither institution has published results.

What the Experts Are Saying

At ETH Zurich, researchers in the Information Science and Engineering department have been studying institutional image redundancy since at least 2022. Their published work points to a compounding effect: when organisations migrate from one content management system to another — as many Swiss public bodies did during the pandemic-era digitisation push — duplicate files multiply at each migration stage. One peer-reviewed paper from the group, published in the journal Digital Libraries Quarterly in late 2024, found that mid-sized European municipal archives averaged a 34 percent duplication rate across image holdings after a system migration.

Informatik Zürich, the city's internal IT directorate headquartered near Hardturm, has reportedly been piloting a deduplication protocol across four departments since early 2025. The program draws on perceptual hashing technology — software that generates a fingerprint for each image file and flags near-identical matches — rather than relying solely on file-name comparisons, which catch only the most obvious duplicates. Practitioners in the field describe the distinction as significant: two scans of the same planning document saved under different names would pass a filename check but fail a hash comparison.

Professionals at the Zentralbibliothek Zürich, which holds digitised collections dating back several centuries, have raised a related concern about what they call "replacement drift" — the tendency for a corrected or updated image to sit alongside its predecessor in the same archive folder, with no metadata flag distinguishing them. Without clear versioning, researchers and automated systems alike may pull the wrong file.

Costs, Compliance, and What Comes Next

The financial dimension is not trivial. Cloud storage contracts for Swiss public institutions typically run on tiered pricing, and several Zurich-area bodies moved significant portions of their holdings to cloud infrastructure between 2021 and 2024. Industry benchmarks suggest that eliminating confirmed duplicates from a mid-sized institutional archive can reduce active storage costs by between 15 and 25 percent — a meaningful figure when annual contracts run into six figures in francs.

The Stadt Zürich published a digital strategy roadmap in March 2025 covering the period through 2028. The document identifies data quality, including file-level deduplication, as a priority area, though it does not specify budget allocations for image management specifically. The cantonal government has been less forthcoming about timelines.

For organisations looking to act before the January 2027 federal deadline, practitioners in the field broadly agree on a sequenced approach: audit first using hash-based tools, establish a versioning policy before any deletion begins, and ensure that removal logs are retained for compliance purposes. Deleting a file that turns out to be the only surviving copy of a historically significant image is not a recoverable error.

On Rämistrasse, where several of Zurich's major cultural and research institutions cluster, the practical pressure is already visible in procurement decisions. At least two institutions in that corridor put out tenders in the first half of 2026 for digital asset management systems that listed deduplication capability as a required, not optional, feature. The market, it seems, has already read the direction of travel.