Shawshank Prison isn’t a real prison at all. The only real shots were the exterior ones done outside the abandoned Ohio State Reformatory in Mansfield. The inside of the reformatory was such a disaster that the filmmakers shot the interior shots on a sound stage.
They figured it would be cheaper to create a replica than try to renovate the decaying jail. They definitely fooled us (and the Academy). The set design was so convincing that everyone thought it was filmed in a real prison.
The Recording Problem
Morgan Freeman had to record his iconic voice-over twice. The first time took only 40 minutes and was played out loud during filming to set the rhythm of each scene. So why did they record the voice-over a second time? Well, the first recording had a hiss that the movie's sound engineers couldn't fix.
Since the first recording couldn't be used in the final cut, Freeman had to do it a second time. Though this time, it took the actor three weeks to complete. Who said art was supposed to be easy?
A Change of Title
Stephen King's original title was 'Rita Hayworth and the Shawshank Redemption'. The studio shortened the title, not because it was too long, but because many people in the film industry thought the film was going to be a biopic of the actress. Young actresses and supermodels sent audition requests to play Rita.
What they didn't know was that Rita Hayworth (the real one) only appears once in 'The Shawshank Redemption' when her film 'Gilda' is played to the inmates on movie night. The movie never needed anyone to portray Rita.
Shawshank References
Stephen King loves Maine. He loves it so much that he lives there, and also sets many of his diabolically frightening novels in the Pine Tree State. 'The Shawshank Redemption' is no exception. What King also loves to do is interconnect his books. Shawshank is mentioned in many of his works.
In the film 'Dolores Claiborne', based on one of King's novels, Dolores yells at her husband that he will do time in Shawshank for what he did to their daughter. Shawshank Prison is also mentioned in 'The Fifth Quarter', 'Needful Things', 'Sun Dog', and more.
The Extras Were Ex-Cons
Every filmmaker deals with obstacles. Extras, even though their roles are minor, are still needed to make prison look like a prison and not a ghost town with barred windows. The inmates were supposed to be portrayed by the local inhabitants, but they left after one day of shooting to go back to their regular nine to fives. So, the director had to find a quick solution.
To get the extras they needed, the production team went to a halfway house. Many of the inmates in the movie were real ex-cons. So it's safe to say that they were ready for their roles.