Zurich's Digital Archives Are Drowning in Duplicate Images — and Officials Are Finally Talking About It

Zurich's public institutions are sitting on a problem that has quietly compounded for years: vast digital archives stuffed with redundant, duplicate images that inflate storage costs, slow research workflows, and increasingly complicate compliance with Switzerland's revised data-management standards. City archivists, university librarians, and technology procurement officials are now, with unusual openness, acknowledging the scale of the mess.

The issue has sharpened in 2026 for a specific reason. A federal ordinance update that came into force in January requires cantonal institutions to demonstrate structured, auditable digital asset management before their next budget review cycle. For Zurich, that deadline lands in the fourth quarter of this year. Institutions that cannot show clean, deduplicated repositories risk having discretionary IT funding frozen — a real lever in a city where digital infrastructure budgets have already faced scrutiny in the wake of the UBS-Credit Suisse consolidation and its ripple effects on cantonal financial planning.

What the Institutions Are Saying

ETH Zurich's main library on Rämistrasse has been among the more candid voices. Library services staff have described — in public presentations to the university's IT governance board — image duplication rates in certain research data collections running well above 30 percent. That figure, cited in a February 2026 internal governance document circulated to faculty IT coordinators, represents not just wasted server space but a real obstacle to reproducibility checks in published research. The library has been piloting a deduplication workflow using open-source tooling since March, targeting its natural sciences image repository first.

The City of Zurich's Stadtarchiv, housed near Neumarkt in the Altstadt, is dealing with a different but related challenge. Its digitisation programme — which accelerated through 2023 and 2024 to process historical photographic collections from the Baugeschichtliches Archiv — generated multiple file versions of thousands of images as different scanning operators worked in parallel without a unified naming convention. A project to reconcile those duplicates was budgeted at CHF 180,000 for 2026, according to the city's published IT supplementary budget approved by the Gemeinderat in December 2025.

At Stadtspital Zürich Triemli in Altstetten, the problem takes on a sharper edge. Medical imaging departments have long grappled with duplicate DICOM files — the standard format for radiology scans — created when patients are re-registered across different intake systems. Hospital IT governance officials raised this at a canton-wide health digitisation forum held at the Kongresshaus in March. The concern is not merely administrative: duplicate images in a clinical record can, in a worst case, mean a clinician reviews an outdated scan. Triemli's IT team has been working with a Zurich-based software vendor since February to implement hash-based duplicate detection across its radiology archive.

A Practical Reckoning

Technology specialists working across Zurich's public sector point to a shared root cause: institutions rapidly expanded their storage capacity during the pandemic-era digitisation push without simultaneously investing in governance frameworks. Hard drive space was cheap; protocols were not enforced. Now storage is not the bottleneck — findability and legal traceability are.

The Zurich Cantonal Government's chief digital officer directorate circulated a guidance note in May 2026 recommending that all cantonal bodies adopt a minimum standard of perceptual hash comparison — a technique that identifies visually identical images even when file names or metadata differ — before the end of the third quarter. The note does not mandate a specific tool, but it sets a benchmark that effectively rules out purely manual review for any archive larger than 10,000 files.

For institutions still in the early stages, the practical path forward is clearer than it might seem. Technology officers advising multiple Zurich bodies recommend starting with the highest-volume ingest points — document scanning stations and automated backup processes — rather than attempting a full historical audit first. Fixing the pipeline matters more than immediately cleaning the pool. The canton's Q4 review will focus on evidence of systematic process, not perfection. Institutions that can show a credible, documented deduplication workflow by October are expected to satisfy the new federal standards, even if their archives are not yet fully clean.