How Istanbul's Visual Archive Ended Up Full of Ghost Images — and What Happens Next

Istanbul's civic and cultural institutions are sitting on tens of thousands of duplicate, mislabelled, or visually redundant images spread across at least a dozen separate digital repositories — a problem that administrators at the Istanbul Metropolitan Municipality's urban documentation unit have been wrestling with since the sweeping digitisation push that followed the 2023 Kahramanmaraş earthquakes triggered urgent re-cataloguing of at-risk heritage sites.

The issue matters now because the city is mid-way through a major public-access project. The Istanbul Archaeological Museums, the Atatürk Library on Taksim Square, and the municipality's own open-data portal are all scheduled to merge their photographic and cartographic holdings into a single searchable platform by the end of 2026. If duplicate images are not resolved before the merger, search results will be polluted with redundant entries, metadata conflicts will multiply, and the legal licensing status of thousands of photographs will remain unclear — complicating use by researchers, journalists, architects, and urban planners.

How the Backlog Built Up

The roots of the problem go back at least two decades. Istanbul's digitisation efforts were never co-ordinated from a single authority. The municipality ran its own photographic archive. The Istanbul Directorate of Surveying and Monuments maintained a parallel registry. Private foundations like SALT Galata, headquartered on Bankalar Caddesi in Karaköy, built their own collections independently. Academic institutions in Beyoğlu and Fatih uploaded images to external platforms with inconsistent tagging conventions. Each institution developed its own file-naming logic, and no shared identifier standard existed to flag when the same physical photograph or building façade had been scanned multiple times from different sources.

The 2023 earthquakes added pressure in two directions at once. On one hand, emergency surveys of vulnerable structures across districts like Fatih, Zeytinburnu, and Avcılar generated thousands of new images in a matter of weeks. On the other hand, institutions realised how much existing material lacked earthquake-risk metadata or geocoordinates. The scramble to update records produced duplicate uploads on a scale that dwarfed anything seen before. Archivists who spoke generally to The Daily Istanbul described backlogs that had never fully cleared.

A 2025 audit commissioned under the municipality's Smart City Action Plan — a programme publicly referenced in Istanbul Metropolitan Municipality documentation — identified image duplication as one of the top three obstacles to the planned unified portal. The audit covered roughly 340,000 digital image files held across five municipal sub-directorates. No final figure for the proportion deemed duplicates has been published, but the Smart City office acknowledged the scope in a public presentation at the Istanbul Congress Centre in Şişli last October.

What Comes Next for the Archive

Work is now underway to deploy automated perceptual hashing — a technique that generates a digital fingerprint for each image, allowing near-identical files to be matched even when they carry different filenames or metadata. The technology is not new; major European city archives in Amsterdam and Vienna adopted comparable tools several years ago. Istanbul's scale makes it technically demanding: the five-directorate set alone runs to tens of terabytes, and the merged portal is expected to eventually absorb material from SALT Galata, the Yapı Kredi Culture Arts archive on İstiklal Caddesi, and the Boğaziçi University library.

Once duplicates are flagged, human reviewers must still decide which version of a given image carries the most accurate metadata and the clearest licensing terms. That step is slower and more expensive. Institutions are working to agree on which file should be designated the canonical record and which should be archived or deleted — a decision with real consequences for historians researching Istanbul's rapid urban transformation along the Bosphorus shoreline and in neighbourhoods demolished and rebuilt after earthquake-safety assessments.

For anyone who submits photographs to the portal after it launches, the practical implication is straightforward: new submissions will be automatically checked against the existing library before being accepted, and contributors will be prompted to claim ownership or licensing rights at the point of upload rather than after the fact. The municipality has said the unified portal will go into public beta before the end of 2026, though no specific month has been confirmed.