See Christian Bale’s Batman screen test (VIDEO)

How do you know when an actor is right for a part?

In light of the huge financial and critical success of Christopher Nolan’s “Dark Knight” trilogy, there’s little doubt in anyone’s mind that English actor Christian Bale was the right man to play Bruce Wayne and his crime-fighting alter ego Batman.

But just like everyone else, Bale had to audition for the part. Other contenders for the original “Batman Begins” role included Jake Gyllenhaal, Billy Crudup, Hugh Dancy, and even future Joker himself Heath Ledger.

So, why did Nolan and company eventually decide on Bale? It apparently had a lot to do with the actor’s strong screen test.

When filmmakers and producers really want to find out if an actor or actress is right for a part, they do what’s called a screen test. Screen tests are done for a number of reasons, but they’re primarily used so that producers can gauge chemistry between co-stars, see how an actor handles the material, and, in the case of many superhero movies, get feel for how an actor will perform and look while in costume. This stage almost always happens after the audition process has narrowed down the potential candidates to just a few.

For Bale’s “Batman Begins” screen test the actor sported Val Kilmer’s batsuit from “Batman Forever” and played opposite his future “The Fighter” co-star Amy Adams (incidentally also “Man of Steel's” future Lois Lane). Bale performs a series of familiar scenes from the film and tests out his gravelly and now iconic Bat-voice -- a characterization that director Christopher Nolan said helped get the actor the part.

"Christian had figured out before the screen test that you could not give a normal performance," Nolan said. "You had to project massive energy through this costume in order to not question this costume. I think Christian's voice was a big part of the impression he made in the test."

Many fans were hoping against hope that Bale would reprise the Caped Crusader role for Zack Sndyer’s upcoming “Man of Steel” sequel, which pits Superman against Batman. There were even rumours that the actor had been offered an astounding $50 million by studio Warner Bros. to do just that. Actor/director Ben Affleck ended up being the studio's choice for Batman going forward, but Bale's screen test is a ready reminder that Affleck has very big shoes (and cape, and cowl) to fill.