Falkenshtein, B. Yu. Photochemical Dictionary: Russian-Latin (Fotokhimicheskiy slovarik: Russko-latinskiy), 1929. In Russian.

Фалькенштейн Б. Ю.
Фотохимический словарик. Русско-латинский. / [Библиотека фотографа; Библиотека журнала «В мастерской природы»].
Ленинград : Научное книгоиздательство, 1929 (Центральная типография Наркомвоенмора).
44 с. : [4] с. объявл. ; 17×13 см. Мягкая издательская бумажная обложка. Тираж 5000 экз.
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Falkenshtein, B. Yu.
Photochemical Dictionary. Russian-Latin. / [Photographer's Library; Library of the Journal "In the Workshop of Nature"].
Leningrad : Nauchnoe Knigoizdatelstvo (Scientific Publishing House), 1929.
44 pp. : [4] pp. ads ; 17×13 cm. Original paper softcover. Edition of 5,000 copies.

This 1929 pocket-sized reference is a specialized artifact from the late NEP era, designed for the practical needs of both professional photographers and dedicated amateurs in the early Soviet Union. Authored by B. Yu. Falkenshtein, the dictionary provides a deep dive into the internal logic of the darkroom, including the arrangement and description of 145 of the most essential chemical substances used in the photographic process. By providing a Russian-Latin nomenclature, the book served as a vital bridge for practitioners navigating the transition from traditional apothecary standards to modern chemical manufacturing. Each entry offers concise data on the properties, uses, and precautions for various developers, fixers, and toning agents, reflecting the high degree of technical self-sufficiency required by photographers during the 1920s.
The volume was published as part of the "Photographer's Library" series, an offshoot of the popular-science magazine In the Workshop of Nature, which played a crucial role in the dissemination of technical literacy across the USSR. Printed by the Central Typography of the People's Commissariat of Military and Naval Affairs (Narkomvoenmor), the physical book is a compact 17×13 cm brochure, complete with several pages of period advertisements that offer a rare glimpse into the photographic market of pre-industrialized Leningrad. Despite a print run of 5,000 copies, these ephemeral technical guides were typically exhausted by heavy workshop use, making well-preserved copies quite scarce. For bibliophiles, historians of science, and collectors of photographic ephemera, this 1929 Leningrad imprint is a vital primary source, documenting the foundational chemistry of early 20th-century visual arts.