Helsinki's Digital Archives Face a Reckoning Over Duplicate Images: What Officials and Experts Are Saying

Helsinki's municipal digital archive system contains tens of thousands of duplicate image files, a problem that archivists at the City of Helsinki Urban Environment Division have been flagging internally for at least two years. The issue has now reached the desks of senior officials, with pressure mounting ahead of the Helsinki City Council's autumn budget review in September 2026, where digitisation spending is expected to feature prominently.

The problem is not cosmetic. Duplicate images — identical or near-identical photographs and scanned maps stored under different file names — consume server storage, slow down search tools used by planners and developers, and introduce errors when outdated versions of images are mistakenly cited in planning documents. The Urban Environment Division, based at Sörnäistenkatu 1 in the Kallio district, manages records covering everything from Kruununhaka's 19th-century streetscapes to recent construction permits in Pasila's rapidly changing rail yard development zone.

What the Specialists Are Saying

Professionals working in municipal data management have been vocal about the scale of the challenge. Specialists at the Helsinki City Library's digitisation unit, which operates partly out of the Oodi central library on Töölönlahtikatu, have pointed to a lack of standardised metadata protocols as the root cause. Without consistent tagging at the point of upload — correct date, photographer, location, resolution — automated deduplication tools struggle to distinguish between a genuine duplicate and two separate photographs of the same building taken from slightly different angles.

The Finnish National Board of Antiquities, known as Museovirasto, which maintains its own overlapping photographic records of Helsinki's built heritage, has raised the issue in inter-agency correspondence reviewed by The Daily Helsinki. Museovirasto's collections include more than 140,000 photographs related to the Helsinki region alone, a figure that makes cross-referencing with municipal archives a formidable task when file naming conventions differ between institutions.

Technology consultants working with Finnish public-sector clients have argued that the solution lies in adopting the W3C's IIIF (International Image Interoperability Framework) standard, which several Nordic cities — including Stockholm's Stadsarkivet — adopted between 2022 and 2024. IIIF allows institutions to share image metadata across platforms without duplicating the underlying files. Helsinki has piloted the standard in limited form through the HAM Helsinki Art Museum's online collection, but full integration across city departments has not happened.

The Cost and the Timeline

Estimates circulating within the Urban Environment Division suggest the city's primary planning image repository holds somewhere between 15 and 20 percent redundant files — a range wide enough to indicate that no precise audit has yet been completed. An independent audit, which city IT procurement rules would require to be put to competitive tender, would likely cost between €80,000 and €150,000 depending on scope, according to comparable public-sector contracts published on the HILMA procurement portal in 2025.

The Kalasatama digital infrastructure project, a smart-city initiative running in the eastern harbour district, has already trialled image-deduplication software from a Finnish vendor as part of its sensor data management work. Planners involved in that project have described the results as encouraging, though the image volumes involved in Kalasatama are far smaller than those in the city-wide archive. Scaling any solution to cover the full Urban Environment Division repository — which spans decades of analogue-to-digital conversion — is a different order of problem.

City Council member discussions ahead of the September budget review are expected to address whether a dedicated line item for archive remediation belongs in the 2027 capital expenditure plan. Without ring-fenced funding, the work tends to fall between departmental mandates: IT sees it as an archiving problem, archivists see it as an IT problem, and planning departments simply work around the clutter.

For residents and developers navigating Helsinki's building permit portal — accessible through the city's Lupapiste platform — the practical consequence is straightforward: searches for reference images of older neighbourhoods like Ullanlinna or Toukola sometimes return the same photograph multiple times, ranked differently by the system's relevance algorithm. Experts recommend cross-referencing any planning image retrieved from the city portal against Museovirasto's Finna.fi database before citing it in a formal application. The September budget discussions will show whether the city is prepared to fix the underlying system, or leave users to work around it.