Istanbul Archives Race to Purge Duplicate Images From Digital Collections This Week

Istanbul's sprawling municipal archive network moved decisively this week to address a problem that had been quietly undermining years of digitisation work: thousands of duplicate image files clogging repositories maintained by the Istanbul Metropolitan Municipality and the Atatürk Library on Beyazıt Square. The redundant files, accumulated over multiple scanning drives since 2023, had inflated storage loads and generated conflicting catalogue entries that sent researchers down dead ends.

The timing is not accidental. Turkey's State Archives Directorate issued a circular in late June 2026 setting a 31 July deadline for municipal and university libraries receiving federal digitisation grants to audit and clean their digital holdings. Institutions that miss the deadline risk losing access to the next funding tranche, which covers equipment upgrades and staff training through 2027.

What Happened This Week

Teams at the Atatürk Library, housed in a 1939 building that itself survived Istanbul's twentieth-century demolition waves, began running automated deduplication software on Monday. By Thursday, preliminary scans had flagged approximately 18,000 image files as likely duplicates across collections covering Ottoman-era property maps and early Republican-period street photography from Karaköy and Galata. Staff are now manually reviewing a subset of those flags before any permanent deletion, a precaution librarians say is essential when dealing with fragile historical material that may exist in only one physical original.

Across the Golden Horn, the Istanbul Research Institute on İstiklal Caddesi — a private foundation with one of the city's richest collections of historic Bosphorus photographs — completed its own deduplication pass on 2 July. The institute reported that roughly 12 percent of its digitised image catalogue, built up since 2019, contained at least one duplicate entry, a figure that tracks with benchmarks reported by European municipal archives running similar audits. Duplicate images had appeared partly because different scanning contractors used inconsistent file-naming conventions, and partly because images donated by private collectors were ingested without cross-checking existing holdings.

Storage is money, and in a country where data-centre costs are priced in dollars against a lira that has lost significant value since 2021, the problem compounds quickly. A single high-resolution TIFF scan of an Ottoman cadastral map can run to 400 megabytes. Multiply that by tens of thousands of duplicates and the waste becomes a genuine budget line item for institutions already stretched by inflation.

Why Researchers and Heritage Workers Are Paying Attention

For anyone who has spent time in Istanbul's archive reading rooms — the Municipality's documentation centre in Fatih, or the specialist rooms at Boğaziçi University's Kandilli Campus — duplicate records are a practical frustration that goes beyond tidying up hard drives. When the same photograph carries two different catalogue numbers with contradictory metadata, the error propagates into academic papers, municipal planning documents, and increasingly into the AI-training datasets that heritage institutions are beginning to license to technology companies.

The Istanbul Metropolitan Municipality's digital transformation office, which has been coordinating with district municipalities from Beşiktaş to Kadıköy on shared infrastructure since early 2025, signalled this week that deduplication standards will be folded into a revised data-governance protocol expected to be published in September. The protocol would, for the first time, set a common file-naming standard across all borough-level archives that feed into the central system.

Earthquake preparedness also sharpens the stakes. After the February 2023 Kahramanmaraş disaster underlined how quickly physical records can be destroyed, Istanbul's heritage community accelerated digitisation. Speed, though, created quality problems — and this week's cleanup is partly a consequence of decisions made in the urgent months that followed.

Institutions working through the audit have until 31 July to submit compliance reports. For researchers planning visits, the Atatürk Library is advising that catalogue searches in the Ottoman maps and early-Republican photography collections may return incomplete results until the review concludes, likely around 20 July. The Istanbul Research Institute says its online portal on İstiklal Caddesi remains fully searchable, with flagged duplicates now clearly labelled rather than hidden, giving users transparency about which entries are still under review.