Istanbul's Urban Archives Race to Strip Out Duplicate Images as Digital Heritage Drive Hits New Phase This Week

Istanbul's digitisation push hit a practical wall this week. Staff at the İBB Şehir Kütüphanesi — the Istanbul Metropolitan Municipality's city library system headquartered in Beyoğlu — began a systematic pass through roughly 340,000 scanned images catalogued since 2021, pulling out duplicate entries that have quietly inflated the archive's apparent size while frustrating researchers trying to locate unique material. The cleanup, which started Monday, is the most significant audit of the collection since the original scanning drive launched under the municipality's Smart City directorate.

The timing matters. Turkey's cultural ministry has been pressing major institutions to submit clean, deduplicated datasets to a national heritage portal by September 1, 2026. For Istanbul, which holds more catalogued Ottoman-era visual material than any other city in the country, that deadline is both an opportunity and an embarrassment: the duplicates in question are not a minor clerical nuisance. Early assessments by the library's digital assets team indicate that a substantial share of the photographic records tagged under Boğaziçi and Tarihi Yarımada subject headings contain two or more identical scans filed under different accession numbers.

Why Duplicate Images Became Istanbul's Archive Problem

The root cause is familiar to anyone who has watched a large institution try to go digital fast. Between 2021 and 2024, the İBB digitisation programme contracted scanning work to at least three separate vendors, each using its own metadata schema. Images were ingested into the central system without a mandatory deduplication step. A photograph of the Galata Tower taken from the Karaköy waterfront, for example, might exist in the archive as many as four times — scanned from different physical copies of the same print, or uploaded twice during a file-transfer error, or catalogued once in Turkish and once with a transliterated English tag.

The Istanbul Photography Museum (İFSAK-affiliated, based in Beyoğlu's Tünel district) flagged the problem formally in a letter to the municipality in March 2026, after its own researchers reported repeated dead-end searches in the shared catalogue. That correspondence is understood to have accelerated this week's internal review, though the municipality has not yet issued a public statement on findings or timelines.

Duplicate image management is a known pressure point in large-scale heritage digitisation. The British Library's 2023 annual report on its own digitisation programme noted that deduplication workflows added an average of 11 weeks to processing timelines — a benchmark that Istanbul's teams are reportedly using as a planning reference. The İBB library system spans 53 branches across the city's European and Anatolian sides, and the digital archive feeds directly into school curriculum tools used by the Istanbul Provincial Directorate of National Education.

What the Cleanup Actually Involves

The practical work is being done by a six-person team using open-source perceptual hashing tools — software that compares images pixel-by-pixel and flags near-identical files even when file names or metadata differ. Each flagged pair must then be reviewed manually before any record is retired, because some apparent duplicates are actually distinct images taken seconds apart and both considered archivally significant. The Rumelihisarı fortification collection, for instance, contains sequences photographed during 1950s restoration work where sequential frames document structural change — deleting the wrong one would be an irreversible loss.

Researchers working with the Boğaziçi Üniversitesi history department, which uses the İBB digital catalogue for several ongoing urban studies projects, have been told to expect intermittent access disruptions through the end of July as records are locked for review. The municipality's digital services portal at dijital.ibb.istanbul.gov.tr shows a maintenance notice posted Wednesday.

The September 1 national deadline will not move. Institutions that fail to submit clean datasets risk losing their priority status in the next round of ministry digitisation grants, which are expected to be announced in the fourth quarter of 2026. For Istanbul's archive teams, the next eight weeks are about more than tidy filing — they are about securing the funding that keeps the entire project alive. Anyone with research requests pending against the Tarihi Yarımada or Boğaziçi image collections should contact the İBB Şehir Kütüphanesi directly to confirm whether specific accession numbers remain active during the review period.