Istanbul Races to Purge Duplicate Images From Its Digital Heritage Archives — and Lags Behind Istanbul's Own Ambitions

Istanbul's municipal digital archive holds more than 2.3 million scanned images — photographs, maps, architectural drawings, and cadastral records accumulated across decades of digitisation projects — but a significant share of that collection is redundant. Duplicate entries, some filed three or four times over, are slowing search performance and inflating storage costs at the İBB Kültür A.Ş. archive centre near Fatih, according to procurement documents published on the Istanbul Metropolitan Municipality's public procurement portal earlier this year.

The problem is not unique to Istanbul. But how cities resolve it increasingly separates functional digital heritage infrastructure from expensive hard-drive graveyards. With Ayatollah Khamenei's funeral this week drawing global attention to how institutions manage and transmit historical records under pressure, and with Turkish cultural agencies still processing roughly 180,000 new scans annually from post-2023 earthquake salvage operations in Hatay and Kahramanmaraş, the pressure on Istanbul's archivists has reached a practical threshold.

The Duplication Problem in Concrete Terms

The core issue is structural. Istanbul's municipal digitisation effort has never operated from a single platform. The İstanbul Araştırmaları Enstitüsü in Beyoğlu, the Atatürk Kitaplığı on Millet Caddesi in Fatih, and the separate digital repositories maintained by the Vakıflar Genel Müdürlüğü have all scanned overlapping collections — particularly photographs from the late Ottoman and early Republican periods — without a unified deduplication protocol. A 1920s panorama of the Golden Horn, for instance, may exist in all three systems under different metadata tags, different file names, and different resolution standards.

Storage costs are not trivial. Cloud archiving at the scale Istanbul operates runs to several hundred thousand lira per terabyte annually, and with the lira's purchasing power still under sustained pressure — the central bank's benchmark rate stood at 46 percent as recently as early 2026 — every redundant gigabyte carries a real budget consequence. The İBB's 2026 technology budget, published in December 2025, allocated 890 million lira to digital infrastructure across all departments, but line items for archive rationalisation remain modest relative to the overall figure.

Amsterdam's Stadsarchief completed a deduplication overhaul of its 750,000-image digital collection in 2023 using a perceptual hashing algorithm that cross-referenced pixel fingerprints rather than file names — a method that caught near-duplicates created by different scanning hardware. Seoul's National Folk Museum finished a similar exercise in 2024, reducing its active digital image count by roughly 18 percent while making remaining records faster to retrieve. Both cities did so through centralised mandates from single governing bodies. Istanbul has no equivalent single authority over its dispersed archive network.

What Comes Next for the Bosphorus City's Collections

The İBB's technology directorate circulated an internal working paper in March 2026 — referenced but not published in full on the municipality's transparency portal — proposing a pilot deduplication project confined initially to the Atatürk Kitaplığı's photograph collection, which numbers around 340,000 items. If approved and funded, the pilot would run through the end of 2026 and inform a broader rollout across partner institutions in 2027.

The practical stakes extend beyond storage efficiency. Turkey's Ministry of Culture has flagged Istanbul as a candidate city for a UNESCO-aligned digital heritage certification programme, the application window for which opens in early 2027. Duplicate-heavy, inconsistently tagged archives would likely count against that application. Cities that have already received the certification — including Prague and Lisbon — each demonstrated clean, deduplicated collections as part of their submission documentation.

For researchers working in the reading rooms at the Beyoğlu institute or ordering digital reproductions of Bosphorus construction records through the İBB's online portal, the immediate advice is straightforward: cross-reference any image obtained from one Istanbul repository against at least one other before citing it as a unique source, since metadata errors on duplicates sometimes include incorrect dates or misidentified locations. The fix, when it comes, will be institutional. Until then, the workaround is manual.