sentences:  Buying the readymade photographic materials was much more convenient than handmaking their own and soon Bulla's plates became popular, selling not only in St.Petersburg but across the whole Russian Empire.In February 1876 Bulla requested his naturalization and in July 1876 became a subject of the Russian Empire.In 1875 Bulla opened his first photographic studio at 61 Sadovaya Street and soon became a fashionable photographer.