How Zurich's Digital Archives Ended Up Full of Duplicate Images — and Why It Took Years to Notice

Zurich's municipal administration confirmed this week that a structured review of the city's digital image repositories has uncovered widespread duplication across several departmental databases, a problem that archivists and records managers say accumulated quietly over more than a decade of uncoordinated digitisation drives.

The issue matters now because the city is mid-way through an ambitious programme to consolidate its digital infrastructure under the Zürich Digital Masterplan, a multi-year initiative coordinated out of the Stadthaus on Stadthausquai. Duplicate image files — sometimes numbering in the thousands across a single departmental folder structure — inflate storage costs, complicate legal disclosure requests, and undermine the reliability of public-facing archives that journalists, researchers, and citizens consult daily.

How the Duplication Built Up

The roots of the problem stretch back to the early 2010s, when individual city departments began their own digitisation projects without a shared technical standard. The Stadtarchiv Zürich on Neumarkt, which holds the authoritative historical record for the municipality, operated under different protocols than departments such as Tiefbau, Stadtentwicklung, and the various communications offices that generate the bulk of photographic output each year. When those departments eventually migrated to shared servers, their image libraries merged without deduplication scripts — and the duplicates came along for the ride.

ETH Zurich, whose information science researchers have studied municipal data governance in Swiss cities, has published work noting that fragmented digitisation timelines are among the most common causes of redundant file proliferation in public-sector archives. The pattern in Zurich mirrors findings from similar audits conducted in Geneva and Basel over the past five years, where consolidation projects revealed duplication rates running between 18 and 34 percent of total image file counts.

The Zurich case also reflects a broader tension that emerged from the 2022 UBS-Credit Suisse period, when Swiss institutions of all kinds came under pressure to demonstrate tighter internal controls. Municipal technology officers, aware that scrutiny of public-sector efficiency had sharpened, pushed forward with the infrastructure review sooner than originally scheduled. The image duplication problem surfaced as a byproduct of that accelerated audit rather than through any dedicated records management initiative.

The Cost and What Happens Next

Storage is not cheap. Cloud and hybrid storage contracts for Swiss public bodies have risen sharply since 2023, with industry benchmarks placing managed municipal data storage in Switzerland at between CHF 0.04 and CHF 0.09 per gigabyte per month depending on the tier and redundancy requirements. Departments carrying years of unresolved duplicate image files are, in effect, paying repeatedly to store the same pixel data — a mundane inefficiency that compounds into material budget waste at scale.

The Stadtarchiv, working alongside the city's central IT services unit based in the Leutschenbach district, is now piloting automated deduplication software on a subset of planning department images dating from 2010 to 2018. The pilot is expected to conclude by the end of the third quarter of 2026, with a full rollout across all departmental repositories targeted for the first half of 2027.

For ordinary residents who use Zurich's open data portal — accessible under the Stadt Zürich Open Government Data programme — the practical change will eventually be faster search results and more reliable metadata. Images mislabelled or duplicated under conflicting file names have historically caused mismatches when citizens or journalists search for records related to specific building projects or neighbourhood planning consultations, particularly in high-activity zones such as Zürich-West and the Hardbrücke corridor, where urban development photography is dense.

The deduplication project will also require staff training. The Stadtarchiv has flagged that its current team of qualified archivists is stretched, a staffing reality that partly explains why the problem was not caught earlier through routine quality checks. Recruiting digitisation specialists in Zurich's tight labour market, where technology sector salaries set a high floor, remains a constraint that the administration has not yet publicly resolved.