Max: You are quite right about JOURNEY INTO FEAR. Welles was directing THE MAGNIFICENT AMBERSONS by day, and working on JOURNEY INTO FEAR at night. When he finished . . . AMBERSONS, and his scenes in . . . FEAR, he was away to Brazil, and the faithful Norman Foster completed JOURNEY INTO FEAR, but the script Welles and Joseph Cotton collaborated on was much more complex in scope, a kind of vestpocket CITIZEN KANE about the Balkans arms trade. Scenes were shot which rounded out the characters of many of the passengers on the ship, and Richard Bennett (the Captain) was to be a major character. The film was ruthlessly cut into a standard thriller of the day. The theme and template were better realized two years later in Negulesco's THE MASK OF DIMITRIOS, which made a star of Zachary Scott in a Wellsian part, another Ambler tale involving Colonel Haki of the Turkish police, shot in the style of CITIZEN KANE . (And of course, Welles returned to the subject in M. ARKADIN.)
Flint, I am not attacking your position. I'm simply pointing out that some of the films under discussion may have been directed, in part or whole, by Orson Welles but it is the name registered as the director, which settles the matter. (Here, I agree with Blunted.) Welles co-wrote, planned and set up JOURNEY INTO FEAR. The film is obviously a Welles film, but he generously (as was often remarked in those days) gave full credit to Foster.
And Blunted, you are quite correct that Welles had such interest and knowledge in Cagliostro that Gregory Ratoff, back in his beloved Europe after the War, was content to allow him to direct most of BLACK MAGIC, a film which Welles dominated. (On the positive side, Welles did strengthen a bond with Akim Tamiroff, whom he knew through Preston Sturges.) Unfortunately, the film is pretty negligible. In fact, as you suggest, Blunted, Welles attempted to direct a number of films which followed, such as THE PRINCE OF FOXES (King, 1949) and THE BLACK ROSE (Hathaway, 1950), at least when they involved his scenes, or those of Mercury players. (I have read an account by Cinematographer Jack Cardiff how Welles, playing Kubla Khan in animal skins and huge padding under a North African sun, kept spoiling take after take because assigned Director Henry Hathaway would not agree to his interpretation of a scene.)
On the other hand, though not a piece of Wellsian direction, a combination of John Ford (Cinematographer Joe August, Jane Darwell, etc.) and Welles (Composer Bernard Herrmann, ) is clearly and happily evident in German Expressionist Director William Dieterle's THE DEVIL AND DANIEL WEBSTER (in production on the same RKO lot as CITIZEN KANE in 1941), a story which Welles had done twice in the form of economically told radio plays. Max Reinhardt, who was one of Welles' gods, brought Dieterle to Hollywood (A MIDSUMMER NIGHT'S DREAM, 1936), and no other Dieterle American film shows the suppleness of THE DEVIL AND DANIEL WEBSTER. If some collaboration (amazingly) did not take place there, it is generally agreed that British Director Robert Stevenson, new to Hollywood, deferred to Welles on JANE EYRE in the handling of many scenes, especially those involving him and Mercury Player Agnes Moorehead.
It is also agreed by a number of parties present that THE THING FROM OUTER SPACE was directed, in part, by Welles after his friend, Howard Hawks, turned the film over to fledgling director, Chris Nyby.
Blunted, we have been through THE THIRD MAN before. No one is saying that Welles wrote and directed the whole thing, but again, accounts by a number of those present credit him with writing (or re-writing) and directing some of the scenes in which he appeared.
As to MONSIEUR VERDOUX (1947), Charlie Chaplin gives credit on the film to Welles for contributing the idea on which it was based, and Welles told Peter Bogdanovich that he wrote the script largely used by Chaplin in hopes of a full collaboration. The awkward NEW ORLEANS (Lubin,1947) eventually emerged from a promised epic biopic on the life of Louis Armstrong, as part of IT'S ALL TRUE. About the same time, Welles wrote a script for CYRANO DE BERGERAC, but Selznick refused to give up the rights, even when Welles provided the narration for DUEL IN THE SUN as a favor. George Cukor's KEEPER OF THE FLAME (1943) is a KANE-like expose of Senator Bankhead (which Welles' good friend Tallulah must have signed off on, at some point).
Finally, Blunted, you must realize that first time director Henry Jaglom would not have been able to launch his career in A SAFE PLACE without the aid of Welles. He welcomed Welles' help, remained a friend until the end of Welles' life, and incorporated Welles doing a magic trick into the logo of his ongoing company, International Rainbow Pictures, which has supported Oja Kodar in recent years.
Can anyone add anything else here?