The Invisible Ray (1936) was a science fiction/horror film starring Boris Karloff (credited as "KARLOFF") and Béla Lugosi. After The Raven (1935) with its themes of torture, disfigurement, and grisly revenge had performed poorly at the box office and had indirectly led to an alleged ban of
horror films in Great Britain, Universal Studios opted for a more science-fiction themed plot for The Invisible Ray (1936).
In this film it is science not the supernatural that is the source of the terror. When a scientist Dr. Janos Rukh, played by Karloff, is exposed to a rare element called Radium X, he becomes a luminescent murderous fiend. The storyline is great if one can overlook the really bad science. As Karloff’s character explains his discovery to his guest it becomes quite evident that science was not one of screenwriter John Colton's better subjects in high school.
The film's director, Lambert Hillyer, directed more than 160 films between 1917 and 1949. He also wrote 54 films and is noted for directing Dracula’s Daughter (1936) and the 1943 Batman 15-chapter serial. His mother was silent film actress Lydia Knott, who was known for appearing in A Woman of Paris: A Drama of Fate (1923), The Little Diplomat (1919) and The Hushed Hour (1919).
The scene where Karloff is lowered into the pit containing the Radium X meteor was later reused in the Universal serial, The Phantom Creeps (1939) , starring Bela Lugosi. Making Karloff essentially a stunt double for Lugosi, since in the sequence in The Phantom Creeps (1939) it was Lugosi’s character that is lowered into the pit. Many of the sets and sound effects were later used in the Flash Gordon movie serials. The church, in which Frank Lawton and Frances Drake get married, though called the "Church of the Six Saints" in the film, is actually the set of Notre-Dame Cathedral from The Hunchback of Notre-Dame (1923).
During an interview, Frances Drake who played Diane Rukh (Karloff’s wife) in the film, told author Gordon B. Shriver:
"Boris was a very intelligent, rather serious man, and a very effective actor. During the making-of The Invisible Ray, he was interested in establishing the Screen Actors Guild. Very pleasant to work with, no temperament on the set, and seemed to get on well with Bela Lugosi. In fact, the whole picture went very smoothly. We had an extremely efficient cast and director. I think that if Boris had not become an actor, he might have gone into politics, and he would have done well with his good voice and beautiful eyes."
Along with Karloff, Lugosi, and Drake the cast featured a well-known troupe of actors including:
Frank Lawton (Ronald Drake) who is best-known for his title role in the MGM film, David Copperfield (1934) also is noted for portraying J. Bruce Ismay in A Night to Remember (1958).
Walter Kingsford (Sir Francis Stevens) who was known for portraying authorian figures, such as noblemen, heads of states, doctors, police inspectors and lawyers. He was a prolific television actor during the mid-1950s. He had a recurring role as Dr. P. Walter Carew in the popular Dr. Kildare (and Dr. Gillespie) film series.
Beulah Bondi (Lady Arabella Stevens) has the distinction of playing James Stewart’s mother in four separate films: Of Human Hearts (1938), Vivacious Lady (1938) Mr. Smith Goes to Washington (1939) and It's a Wonderful Life (1946).
Frank Reicher (Professor Meiklejohn) an actor, director, and producer, he appeared in King Kong (1933) and The Son of Kong (1933) as Captain Englehorn. His last Hollywood role was in the very first theatrical Superman movie, Superman and The Mole Men (1951).