Istanbul Moves to Scrub Duplicate Images From Its Digital Heritage Archive — But Lags Behind Amsterdam and Seoul

Istanbul's Metropolitan Municipality has begun a systematic review of its digital image archive after an internal assessment found that duplicate and near-duplicate photographs had accumulated across multiple public databases, inflating storage costs and complicating access to accurate historical records. The audit, covering repositories managed by the Istanbul Metropolitan Municipality's (IBB) cultural directorate and the Istanbul Planning Agency, identified redundancies running into the tens of thousands of image files, according to municipal budget documentation reviewed for this report.

The timing matters. Turkey is in the middle of a broader push to digitise urban heritage ahead of the Istanbul 2026 Cultural Tourism Strategy deadline, and the IBB has been allocating funds — roughly 180 million Turkish lira earmarked in the 2025–2026 digital infrastructure budget — toward open-data platforms. Bloated, disorganised image libraries undercut that investment directly: search results become unreliable, storage bills rise, and automated cataloguing tools produce errors when fed duplicate data.

What Istanbul Is Doing — and Where It Falls Short

The IBB's effort centres on two specific projects. The Tarihi Yarımada (Historic Peninsula) digital mapping initiative, which documents sites from Sultanahmet to the land walls at Topkapı, has been cross-referencing its image sets using hash-matching software since early 2026. Separately, the Istanbul Archaeological Museums launched a deduplication pass on their online collections portal in February, working through roughly 340,000 digitised artefact photographs. Progress has been incremental. As of late June, museum staff had cleared duplicates from fewer than a third of those files, according to figures cited in the institution's quarterly report.

Compare that with Amsterdam. The Stadsarchief Amsterdam completed a comparable deduplication project across its 750,000-image municipal archive in under 18 months, finishing in late 2024, by deploying perceptual hashing algorithms and contracting a specialist digital preservation firm. Seoul's Seoul Metropolitan Archives ran a parallel exercise in 2023, processing more than 1.2 million image records and reducing storage overhead by approximately 22 percent, a figure the city published in its annual smart-city progress report. Istanbul's effort is still fragmented across departments that do not share a unified content management system — a structural gap both Amsterdam and Seoul had addressed before beginning their deduplication work.

Karaköy-based digital preservation consultancy firms that work with Turkish public institutions say the challenge is compounded by the sheer number of agencies involved. The IBB, the Culture Ministry's regional directorate, the Istanbul Development Agency (ISTKA), and university-linked repositories such as those at Boğaziçi University all hold overlapping image collections with no common metadata standard. Without harmonised tagging — consistent field names for date, location, and subject — even sophisticated deduplication software will miss near-matches sitting in separate siloed databases.

Why Heritage Images Specifically, and What Comes Next

The stakes go beyond bureaucratic tidiness. Istanbul's post-2023 earthquake preparedness planning relies partly on accurate before-and-after photographic documentation of vulnerable structures. The 2023 Kahramanmaraş earthquakes demonstrated how quickly verifiable baseline images can become legally and operationally critical when assessing structural damage and insurance claims. Duplicate or mislabelled photographs of, say, a 19th-century han in Eminönü or a Byzantine-era cistern in Fatih could create disputes about pre-disaster condition. Municipal planners have flagged this risk internally, though a formal policy response is still pending.

For residents and researchers, the practical advice is straightforward: if you are accessing public image databases through the IBB's open-data portal or the Istanbul Archaeological Museums' online collection before the audit concludes, treat search results with caution. Duplicate entries may appear as separate records with different catalogue numbers. The IBB has said it expects to complete the first phase of its deduplication review — covering the Tarihi Yarımada dataset — by September 2026. A second phase, bringing in ISTKA-linked repositories, has no confirmed start date.

Amsterdam and Seoul took roughly two years each to do this properly. Istanbul is attempting something more complex, across a city of 15 million people with dozens of independent cultural institutions. The timetable, if it holds, would represent real progress. Getting there will require the kind of cross-agency coordination the city has historically struggled to sustain.