Istanbul's Digital Archives Race to Purge Duplicate Images Ahead of New Municipal Heritage Platform Launch

Istanbul's municipal cultural bodies moved this week to formally address a problem that has quietly plagued their digital infrastructure for years: tens of thousands of duplicate images clogging the shared photo archives used by tourism boards, urban planning offices, and heritage institutions across the city. The effort, coordinated through the Istanbul Metropolitan Municipality's digital services directorate, is a precursor to the planned October launch of a unified heritage image platform intended to serve researchers, journalists, and city planners alike.

The timing matters. The municipality has been under pressure to modernise its data systems since a 2024 audit flagged redundant file storage as a source of unnecessary IT expenditure — a sensitive issue given persistent Turkish lira inflation that has squeezed departmental budgets. Consolidating and deduplicating image libraries is now officially listed as a prerequisite before the new platform, internally called the Istanbul Kültürel Bellek Sistemi, or Istanbul Cultural Memory System, can go live.

What Happened This Week

Between Monday and Thursday, technical teams working across three main institutional partners — the Istanbul Archaeological Museums on Alemdar Caddesi in Sultanahmet, the Atatürk Library in Taksim, and the Istanbul Metropolitan Municipality's GIS and data unit in Saraçhane — conducted parallel sweeps of their photographic holdings. According to documents circulated to department heads and reviewed as part of this reporting, the initial sweep identified more than 47,000 image files flagged as likely duplicates across the three institutions, representing an estimated 1.2 terabytes of redundant storage.

The deduplication process uses perceptual hashing software, a technique that identifies visually similar images even when file names or metadata differ — a common problem when photographs of Hagia Sophia, the Galata Tower, or the Grand Bazaar have been uploaded independently by multiple departments over a decade. Institutions have until July 18 to complete their internal reviews before a cross-institutional reconciliation phase begins. Any image flagged for deletion must first be cleared by a heritage officer to ensure no unique historical photograph is lost in the process.

The Atatürk Library, which holds one of the city's most significant collections of late Ottoman and early Republican photography, has been particularly careful. Librarians there have been manually reviewing flagged files rather than relying solely on automated tools, aware that slight variations between two prints of the same scene — different exposure, different cropping — can carry genuine archival value.

Why Duplicate Images Became Such a Problem

The root cause is not difficult to identify. Istanbul's cultural and administrative institutions accumulated digital photo libraries independently, with little cross-institutional coordination, throughout the 2000s and 2010s. Tourism campaigns for neighbourhoods like Balat and Karaköy generated their own photo sets. Earthquake preparedness surveys after the February 2023 Kahramanmaraş disaster added another wave of architectural photographs, many overlapping with existing stock. Urban renewal projects around the Golden Horn created further layers.

The municipality's IT directorate estimates that clearing duplicate images and orphaned files could reduce storage costs by roughly 30 percent — a figure that carries weight at a time when municipal budgets are stretched by inflation running well above 40 percent annually. The savings are expected to be redirected toward expanding broadband connectivity in neighbourhood archives.

For residents and researchers, the practical outcome of the cleanup should become visible once the Istanbul Kültürel Bellek Sistemi opens in the autumn. The platform is designed to allow public searches of authenticated, non-duplicated images tied to specific addresses, historical periods, and building types — a tool that urban planners, neighbourhood associations in places like Fener and Eyüpsultan, and heritage advocates have long requested.

The July 18 internal deadline is firm, according to the circulated documents. Institutions that fail to clear their flagged image queues by then will have files held in a quarantine folder rather than deleted outright, giving teams additional time without blocking the broader reconciliation schedule. If the October platform launch holds, Istanbul would join a small number of European cities — including Amsterdam and Lisbon — that have built publicly accessible, deduplicated municipal image archives in recent years.