I wrote about Adam Sandler yesterday and the way his screen persona doesn't seem a lot different from his real life persona. Persona might be the issue: having played a lot of crude-mouthed characters, perhaps that's the 'image' he now portrays in real life. It's hard to know. Screen actors, more so than stage actors perhaps, tend to mould their parts to themselves, and get parts that are moulded to their natural person. I find Danny de Vito, for instance, always seems to play loud-mouthed, and often foul-mouthed, characters. Different, but similar, to Sandler's.
Denzil Washington, on the other hand, is more in the vein of the gentlemanly person, and rarely plays a villain, especially the sort of villain who has sadistic or violent streaks. Whether these are just outside his natural acting limits, or whether he prefers not to play them, it's hard to know. He has played a few unpleasant characters, but something doesn't quite work, it seems to me, when he does. This is not to say he can't be aggressive or strong, or domineering when required. But in general it's his humanity and warmth that we go to see him for.
Maybe because we seem so close to screen actors we find it hard to distinguish between them and the kinds of roles they play. The camera doesn't let an actor away with a lot; it readily picks up false notes in a screen performance, especially that of a major star. (Character actors and supporting players are a different kettle of fish.) You can sense when a star isn't comfortable in a role. The most recent example I've seen of this was Michael Caine In Educating Rita. Caine playing a professor, even an alcoholic, washed-out professor, just didn't seem to work; and you sensed the actor being out of sympathy with the character in a number of scenes.
Johnny Depp, though he produces great characters, still brings a sensitivity and vulnerability to all his roles. This meant, when he played the writer in secret Window, he could engage our sympathy throughout the movie, and give us a nasty shock at the end when he turned out to be the murderer.
Of course, producers play to their stars' strengths. That's only natural. And I guess if a scriptwriter turns up with a story that requires a crude character in crude situations, then they'll ring Sandler's agent, or de Vito's. There's no way Washington or Depp would fit the bill. And equally, you can't see Sandler in one of the 'commanding presence' roles that Denzil Washington – or Harrison Ford – plays.
I suppose actors get cast to what they do best. Whether that's the best approach is another matter, since it never stretches the actor. Whether stars can be stretched may be another issue as well.