Revealing mistake: When Tommy crumples up the test paper he had written for Andy and throws it into a waste basket the metal container shakes as if he had thrown something heavy. (Telling from the noise it makes the item must have been heavy.) (01:23:30)
Continuity mistake: In the two different shots we have of Tim Robbins getting ready to put the book and folder into the safe for the last time (before he escapes) he collects the book and folder in two very different ways. First time he pulls the book towards the folder. Second time he brings the folder to the book. (01:49:55)
Continuity mistake: When Hank Williams is singing "Lovesick Blues" the MGM label is from 1968. This is meant to be 1963.
Factual error: A single bar of prison-issued soap and a pool of cold, sewage-contaminated water would never be enough to wash the stench that Andy would have acquired from worming through 300 feet of waste.
Suggested correction: Andy could have found an area of cleaner water (say a puddle, small pond, or other ditch) to do a basic cleaning before fully cleaning elsewhere, like a cheap motel.
Suggested correction: First of all it was 500 yards, not 300 feet. Second, all Andy really has to do is go upstream to where the water is clean. I guess you must have also forgotten that has been raining.
Revealing mistake: When Brooks is carving his name, "dust" seemingly like plaster dust vs wood dust is shown falling on the table top, his shoes etc. When they cut to the view of Brooks looking at his work and closing his knife, there is no "dust" on his hand or knife. That much carving with that much dust falling on the table would have left his knife covered with dust. It was clean.
Continuity mistake: The warden pulls out a box of Remington .38 Special cartridges to load his revolver prior to his suicide. The warden empties the cartridges on to his desk and loads the revolver with what are Winchester/Western cartridges.
