The film is credited to the Russian-born Gregory Ratoff, but I daresay most of it was directed by Welles himself. It is far more obviously Wellesian than some of the other films, e.g., Journey Into Fear or Jane Eyre, which he directed uncredited in some part – most notably in a Magnificent Ambersons-like tracking shot where Welles and his accomplice, played by Akim Tamiroff, make their way through the French court.
A note on Akim Tamiroff , Black Magic is the first of several films where Welles, relishing the contrast in their physical appearances, employed the short, round character actor as a sidekick or nemesis. The others are Mr. Arkadin (1955), Touch of Evil (1958), and The Trial (1962). Welles also cast Tamiroff as the ultimate sidekick, Sancho Panza, in his uncompleted Don Quixote.
The screenplay was written by one of England’s most accomplished scenarists, Charles Bennett, writer of Hitchcock’s Blackmail, The Man Who Knew Too Much, The 39 Steps, etc. and Jacques Tourneur’s Curse of the Demon. I once saw Bennett at a Los Angeles County Museum tribute where several scenes from his work were shown. He particularly exulted in a clip from Black Magic where Cagliostro, demonstrating his hypnotic powers, compels a subject to “CRAWL … CRAWL …”
The historical events behind Black Magic also provided the basis for 2001’s Affair of the Necklace, a Hilary Swank vehicle in which Christopher Walken played Cagliostro. Unfortunately, Cagliostro has far too little screen time in this version which consequently lacks the bite of Welles’ film.
And speaking of late ’40s French Revolution noir that you cannot miss, TCM will also be screening Anthony Mann’s masterfully shot Reign of Terror aka The Black Book (1949), with sets designed by William Cameron Menzies, just a few hours later. Happy Bastille Day, indeed.