Istanbul Archives Race to Stamp Out Duplicate Images Flooding Digital Heritage Records

Istanbul's municipal digital archive system has a duplication problem, and this week officials moved to confront it directly. The Istanbul Metropolitan Municipality's Directorate of Cultural Heritage Documentation began a formal audit on July 1, targeting what internal assessments have described as a significant backlog of duplicate and mislabelled images across the city's publicly accessible photo repositories — records that underpin everything from urban planning decisions to tourism promotion.

The timing matters. Istanbul sits at the intersection of several urgent pressures: post-earthquake risk assessments following the February 2023 Kahramanmaraş disaster have driven a surge in digital documentation of at-risk historic structures, while the city's ongoing bid to protect Bosphorus-facing heritage zones has produced a parallel flood of photographic records from multiple competing agencies. When different departments upload images of the same building without standardised metadata, the result is a sprawling, unreliable dataset that no single office fully controls.

What Went Wrong — and Where

The problem is visible in concrete places. The digital catalogue for the Süleymaniye district, one of the most photographed neighbourhoods in the city, currently holds records from at least four separate institutions: the municipality's own heritage directorate, the Istanbul Archaeological Museums, the Fatih District Municipality, and the Turkish Tourism Promotion and Development Agency. Spot checks this week found dozens of near-identical images of the Süleymaniye Mosque complex filed under different metadata tags, different dates, and in several cases different attributed photographers.

Karaköy's historic port warehouses along Kemankeş Caddesi present a similar case. Redevelopment pressure on the area has pushed multiple agencies to document the buildings simultaneously, generating redundant image sets that, when pulled into planning reports, give the misleading impression of a broader photographic survey than actually exists. A municipal working document circulated internally in late June — details of which were described to The Daily Istanbul by a source familiar with the audit process, who was not authorised to speak on record — flagged this specific corridor as a priority for deduplication.

Turkey's State Archives Law, last significantly amended in 2019, does not currently mandate a unified metadata standard for municipal photographic records. That gap has allowed each directorate to develop its own filing convention, and those conventions rarely align. The Istanbul Metropolitan Municipality manages an archive that, as of the directorate's own published 2025 annual report, contains over 1.2 million digitised items — a figure that has grown by roughly 18 percent annually since the post-2019 acceleration of digitisation programs.

The Deduplication Push and What Comes Next

The audit, which is expected to run through September, is using algorithmic matching software to flag visually similar images for human review. The process is being piloted on records covering the Historic Peninsula, specifically the areas between Eminönü and the Topkapı Palace grounds — zones where documentation density is highest and duplication risk is greatest. Results from the pilot phase are due to be presented to the municipality's Culture and Social Affairs Committee before the end of July.

For urban planners and heritage professionals who rely on these archives, the practical consequences of the duplication problem are not abstract. When an image appears multiple times under different catalogue numbers, it can be counted as separate documentary evidence in planning reports, artificially inflating the apparent depth of a survey. In a city where seismic retrofitting decisions increasingly depend on photographic condition assessments of older buildings, that kind of data inflation carries real risk.

The audit also arrives against a backdrop of broader tension over who controls Istanbul's institutional memory. The ongoing political friction between the CHP-led metropolitan municipality and Ankara complicates data-sharing agreements with national bodies, meaning that deduplication across the full landscape of relevant institutions — not just municipal ones — remains a longer-term challenge.

For residents, researchers, or journalists trying to access the city's photographic records through the municipality's open-data portal at data.ibb.gov.tr, the practical advice is straightforward for now: cross-reference any image catalogue number against at least one secondary source before citing it as unique documentary evidence. Until the September audit concludes, the archive's full reliability cannot be taken on faith.