Photographic chemicals were one of the Mallinckrodt Company’s core product lines. Edward Mallinckrodt Sr. began selling Rodinal, a photographic developer, in the early 1890s as a trade agent of the Aktiengesellschaft für Anilin Produktion in Berlin (Agfa). Rodinal was supplied to Mallinckrodt by Arthur Schwarz, a German-American importer based in New York.
In 1892, Schwarz issued the above note on his official business letterhead, which identified him as the sole importer of Rodinal. At the end of the note, he listed Mallinckrodt Chemical Works as the sole trade agent of Rodinal in the United States. The entire note was published in the advertisements section of the American Amateur Photographer 4 (1892).