Conventional wisdom says that Karloff was the better actor of the two — more malleable, elegant, capable of playing “straight” roles — and that Lugosi could only do camp or caricature (partly because he spoke with a thick Hungarian accent, his English was poor, and his features limited him to stereotypical roles). You can see the reasoning behind that argument when watching scenes like the one in The Raven where a bearded Karloff (as a convict on the run) demands that Dr Vollin (Lugosi) give him a new face through plastic surgery: there is something poignant about Karloff’s desperation here, he plays the scene as if he were in a “realistic” dramatic film of the time, and does it very well — while Lugosi is leering and rolling his eyes like he never wants to exit the torture chambers and coffins in the Universal lot.
But I think Lugosi was a personality-actor who could be very powerful and effective within his limited range. He has a surprising sense of humour, for instance, a facility for delivering blackly funny lines, or just for showing exasperation at the naive squares he is surrounded by. (Some of his scenes remind me of another deadpan Central European, Ivan Lendl, telling an umpire, after getting a series of bad calls: “What are you going to tell me next, my house is on fire?”) And he can be unexpectedly moving too, in scenes like the one in The Black Cat where his character learns that his wife and daughter are dead (the former kept preserved in a glass case by a mad architect — but that’s another story).
Anyway, here are some stills from The Black Cat and The Raven featuring these two legends, locked together in posterity. As the Karloff character Poelzig says in one of the finest scenes from that film, an unusual subjective-camera movement through the basement of his Art Deco house, “You say your soul was killed and that you have been dead all these years. And what of me? Did we not both die here in Marmorus fifteen years ago? Are we any the less victims of the war than those whose bodies were torn asunder? Are we not both the living dead?”