JOI's filmography (pp. 990–991)
No cast; liquid-surface holography by Urquhart Ogilvie Jr.; 35 mm.; 7 minutes; enhanced color; silent. […] Note: Archivists in Canada and the U.S. West Coast do not list No Troy but do list titles The Violet City and The Violet Ex-City, respectively, leading scholars to conclude that the same film was released under several different appellations.
Context
No Troy for this theme's ledger: a third holography credit (liquid-surface, Ogilvie again), and the document's instability made explicit — one film, three titles, reconciled only by scholarly conjecture. The elimination content is other themes' business (mined for maps and depression); here it's the technique and the archival wobble.