Yoinked from wikipedia and the IMDB ...
"Son of Frankenstein is the third film in Universal Studios' Frankenstein series and the last to feature Boris Karloff as the Monster as well as the first to feature Bela Lugosi as Ygor. The film was a reaction to the incredibly popular re-releases of Dracula and Frankenstein as a double-feature in 1938. Universal's declining horror output was revitalized with the enormously successful Son, and the studio enjoyed two more decades of popular monster movies.
After director James Whale had departed from Universal Films, Universal selected Rowland V. Lee to direct Son. Lee's film explores dramatic themes: family, security, isolation, responsibility, and father-son relationships. Son of Frankenstein significantly alters the monster's evolving persona from the previous film, Bride of Frankenstein. Gone are his alert intelligence and speech capabilities; in Son, the monster is duller and mute, which is his basic image through not only the rest of the series, but also in the lasting public perception of the character. The monster's brain was obviously damaged in the explosion from the end of the last film, and has reverted into a childlike state. He is immensely fond of Ygor, and finds faith only in him. Although he lost his ability to talk, he obviously remembers his creator, as he sees the resemblance of Henry Frankenstein in Wolf.
The look of the creature is unique in Son. While his physical appearance does not change, he is shown with a fur vest and tall boots. In the previous and following movies in the Universal series depict the monster in a dark suit. Even later movies by different companies tend to follow the trend of a dark suit, making the monster from Son one of the most visually striking versions.
At 99 minutes this was the longest English-language film in the classic Universal horror series (the Spanish version of Dracula (1931) [Drácula (1931)] was about five minutes longer). Most of the films had running times of less than 80 minutes, which served to increase the number of showings possible in theaters.
Makeup artist Jack P. Pierce estimated it took four hours to transform Boris Karloff into the monster. Both Claude Rains and Peter Lorre reportedly were considered for the role of Wolf von Frankenstein; Lorre's casting was publicly announced. This film marks the final time Boris Karloff would play the 'Monster' - at least in a feature film. In August of 1940 he appeared as the Monster in a celebrity baseball game, with Jack P. Pierce in attendance (Pierce was a coach for an amateur baseball team, and played semi-pro when he was younger). In the next Frankenstein film in which Karloff appeared, House of Frankenstein (1944), he played Dr. Gustav Niemann. Originally the Samuel Goldwyn film The Secret Life of Walter Mitty (1947) was to have had a fantasy sequence in which Mitty (Danny Kaye) confronted the Monster, played again by Karloff (who played the villain in 'Mitty.') Goldwyn sought and received authorization from Universal to use the image of the Monster, and Pierce re-created the make-up. Stills exist of the film's director, Karloff, Pierce, and Evelyn Karloff, but it has not been verified that scenes were actually filmed. In the Allied Artists film Frankenstein - 1970 (1958) Boris was an elderly Baron Frankenstein - but the twist ending was the revelation that the Baron had recreated the Monster's face in his own image (i.e., the face of Karloff). The last time Karloff donned the Jack Pierce-style monster makeup was in 'Lizards Leg and Owlet Wing,' a 1962 Halloween special for the TV series 'Route 66' (1960). Thus, he played the "Monster" six times in his career (or 6 1/2, if you count 'Walter Mitty.').
Plans were discussed to shoot the film in Technicolor, but the decision was made to revert to black and white; both director Lee and co-star Josephine Hutchinson verified in later years that the film was designed for, and shot in monochrome. Urban myth has it that Karloff's make-up photographed bright green and was a primary reason for shooting in black and white. An urban myth has it that Dwight Frye was in the Technicolor test reel and was subsequently dropped from the cast.
In the late 1980s a reel of Technicolor test footage was discovered in Universal's vaults, but was either stolen from the desk of the executive who was in possession of it (according to one story) or simply boxed back up by bureaucrats and shipped to a New Jersey film vault (according the film archivist who actually found the reel.) Karloff family home movies shot on the set of the film reveal the Monster's coloration to be grayish with subtle highlights and shadows of blue-green and brick red. The brief clips show Karloff in Monster make-up sticking his tongue out at the camera and pretending to strangle make-up artist Jack P. Pierce can be seen on the CD-ROM The Interactive History of Frankenstein (1995) and 100 Years of Horror (1996), courtesy of Sara Karloff."
The big three. The holy trinity of old school horror. Lugosi, Karloff, and, to a lesser extent, Basil Rathbone. If we're going with a reference to the Catholic holy trinity, then he's the "holy spirit" of the analogy. Invisible and non-existant but still an important part, just not as important as the big two.
Have fun with this one, peeps.
Wind Clan out.
Have fun understanding Lugosi and not yawning at fancy lad Basil Rathbone. Tomorrow we continue our DOWNHILL descent!
Tomorrow: Lon Chaney takes up the big black boots and Lugosi returns in Frankie's official transition to B-movie monster ...