Casting trick #6: Think of performance not in terms of right or wrong, but rather in terms of true or false.

My wife has an audition for a Gus Van Sant movie this morning, which is especially neat for me.

For one thing, I love getting a glimpse at how other, more famous, directors work. For another, my wife is amazingly good at breaking down a scene and constructing an entire world from the clues she finds hidden in dialogue or screen direction.

This time, though, I see the scene one way and she sees it another. And the reality is, neither one of us has a clue how Gus sees it. For all we know, we could both be totally off.

How is that relevant? Because your actors can't know what's in your head.

You can tell them. And you should. But even the most detailed explanation will leave them loads of room to interpret. This is a good thing, by the way. It's what actors get paid to do.

What that means for you doing casting, though, is that you need to think of performance not in terms of right and wrong, but rather in terms of true or false.

One of my wife's lines is, "Mind your business." Is she saying it with anger? Sadness? Frustration? Is she lashing out or muttering? Is she even speaking to the other actor or is she saying it to herself?

Who knows? At this point in the process, I'd be surprised if Gus Van Sant even knows.

My wife needs to fill in the blanks the best way she can, and if you ask me, the way to do that is to have a clear picture of her character first.

I like the idea of her character feigning ineptitude in order to avoid having to confront reality, but my wife is leaning more toward her putting on a false front of optimism in the feeble hope that she can control her fate. Whatever she decides will inform the way the line comes out. That, along with the way the line that precedes it is given to her.

If Gus is any good, and I happen to think he's pretty good, he won't care whether she lands squarely in his headspace. If he were me, he'd evaluate the decisions she'd made given the information she was provided and if he respected her reasoning, would then consider how she executed. Did she listen and react? Was she believable? Did she find the emotional beats?

In other words, was her performance true to the character?

Every once in a while you're going to have an actor walk in and nail exactly what you're thinking the first time at bat. When that happens, suppress the urge to high-five yourself. See what else he or she can give you first.

If you get another interpretation that's just as believable, then by all means, head to the nearest bar for a celebratory cocktail. But if you get the same thing again, you need to realize that if you cast this person, you're going to get what they want to give you, not necessarily what you want to get.

You're the director, after all. That means you're supposed to, you know, direct.