The movie cost almost exactly the same to film as Gone with the Wind (1939), with most of the overruns due to David O. Selznick's constant interference with Alfred Hitchcock's carefully budgeted production and his insistence that Hitchcock do extensive re-shoots. Since Hitchcock required that he receive his contractual $1,000-per-day fee, Selznick took over, including supervising editing and the musical score.
When Keane goes to the Paradine house in Cumberland, he walks over to Mrs. Paradine's piano. On the piano we see close-up of a page of music called Appassionata Op. 69 by Francesco Ceruomo. Francesco Ceruomo is an Italianized version of Franz Waxman, who wrote the background music for the film. The music shown on the piano is the actual music that is playing on the soundtrack at that point.
Greta Garbo turned down the role of Martha in I Remember Mama (1948) around the same time she also rejected the role of "Mrs. Paradine" in The Paradine Case. She is reputed to have commented, "No murderesses, no mamas."
David O. Selznick originally wanted Bernard Herrmann to compose the score for The Paradine Case but Herrmann wasn't available due to other commitments, so Selznick decided to go with Leith Stevens, borrowing him from Universal at the cost of $10,000 for 8 weeks. Stevens composed and recorded nine cues but Selznick rejected them, returning half of Stevens' fee to Universal and returning the music and recordings to the composer. Eventually Franz Waxman was hired to do the score.
A memorable image in The Paradine Case occurs when Mrs. Paradine is taken from her life of luxury and confined to a bare jail cell. The slamming of the iron door behind her as she enters the cell recalls one of Alfred Hitchcock's own memories, that of six-year old Alfred being locked up in the Leytonstone jail.
Although "The Paradine Case" was a box office failure, many critics noticed performances from Ann Todd and Joan Tetzel. Time Magazine (Jan. 12, 1948 issue) commented on their performances with remarks like this - "The only characters who come sharply to life are the barrister's wife (Ann Todd) and her confidante (Joan Tetzel)." Variety Magazine Commented about Ann Todd's performance in "The Paradine Case" like this "Ann Todd delights as his wife, giving the assignment a grace and understanding that tug at the emotions."
The original script for the film was written by James Bridie, and Ben Hecht contributed additional dialogue. But this script wasn't used, because the characters were changed, for example William Marsh became Andre Latour. This script is available at IUCAT Library.
According to Book "Alfred Hitchcock: A Life in Darkness and Light", Hitchcock's favorite effect, he told Charles Higham, had been planned since the inception of The Paradine Case. Keane and Sir Simon Flaquer walk toward the camera as they enter Lincoln's Inn, part of venerable fourteenth-century London law complex. The two are seen entering the building, closing the door, walking up the stairs, turning the corner, heading along a landing into an office, and then continuing into the office, all without a single cut. It was one of Hitchcock's signature composites, using background projection and a treadmill, elaborately planned and prepared in advance by his second unit in London. Opposed to the long take, and oblivious of the significance of Lincoln's Inn, David O. Selznick deleted the shot.
The trivia item below may give away important plot points.
In the original Alfred Hitchcock adaptation by Alma Reville and James Bridie, there was a physical resemblance between Mrs. Paradine and Anthony Keane's wife Gay Keane. But due to casting changes, this idea was dropped altogether.