This one’s easy, right? Not so fast.
Everyone knows that when you use INT. in a scene heading, it means “interior” and when you use EXT. in a scene heading, it means “exterior.” That much is straightforward.
But what happens when you want the subject matter to be inside (e.g. a family eating dinner), but you want to suggest a shot from outside the house (e.g. watching the family through their kitchen window)? Is that INT. or EXT.?
Or what if you wanted to show that someone is inside (e.g. a third-floor apartment), and they’re spying on someone outside (e.g. on the street below)? Is that INT. or EXT.?
Or how about this one: Suppose you wanted to show a truck driving along a highway and indicate we’re also seeing shots that are inside the vehicle. Would this scene heading be okay? INT./EXT. HIGHWAY – DAY
Here’s the trick
Brace yourselves, this tip may be a revelation.
INT. and EXT. don’t indicate where the characters are; they indicate where the camera is.
Boom! Did that just hurt your brain (in a good way)?
So in our first example with the family eating dinner while someone watches from outside, the scene heading would be:
EXT. SMITH FAMILY HOUSE - NIGHT An unknown viewer watches Vic, Tim and the rest of the family through the kitchen window as they blissfully eat dinner. Unaware.
You could also write something like:
We watch Vic, Tim and the rest of the family through the kitchen window as they blissfully eat dinner, safe on the inside. For now.
NOTE: Don’t believe it when people say you should never write: “we watch” or “we see.” It’s great as a general rule (i.e. everything on screen is something we see, so it’s usually redundant), but sometimes it’s unavoidable without a great deal of awkward writing gymnastics. And screenwriting is all about efficiency and clarity.
Let’s look at our second example.
INT. CLARA'S APARTMENT - DAY Clara carefully pulls apart her window blinds. Just enough to see -- An UNUSUALLY TALL WOMAN loping toward her apartment building on the street, three floors below.
See how I’ve broken the above action lines into two paragraphs. That’s because one paragraph should equate to one shot.
I do hate using the less active verb tense though (i.e. “loping” vs. “lope”), even though it’s an acceptable use because it continues the preceding sentence. So I’d probably rewrite things as follows:
Clara carefully pulls apart her window blinds. Just enough to see -- An UNUSUALLY TALL WOMAN. She lopes toward Clara's apartment building on the street, three floors below.
And now for the final example.
We would NOT write: INT./EXT. HIGHWAY – DAY. How can you be inside a highway? Instead write something like:
INT./EXT. BARRY'S TRUCK - DAY
Save the fact that they’re on a highway, or wherever, for the action lines:
The rusty pickup truck barrels along a highway. Inside, Barry and Mary Sue sing along with an old folk tune playing on the radio.
NOTE: Even if you don’t plan on showing anything outside of the truck, it’s always a good idea to use INT./EXT. versus just INT. for driving scenes. Remember, you’re suggesting where the camera is. It’s entirely possible the director would like a shot of the characters through the windshield, for example, which means the camera would be outside of the truck.
INT./EXT. Bonus Round
There’s one other scenario that trips up a lot of writers. What happens if you’re inside a building but outside a character’s apartment, like in a hallway? Would that be INT. or EXT.?
Here’s where semantics get in the way. EXT. doesn’t mean outside of something. It means it’s an exterior shot, as in outdoors.
So you would write such a scene as follows. Let’s revisit Clara:
INT. CLARA'S APARTMENT BUILDING - HALLWAY - DAY Clara cracks open the door to her apartment. Slowly looks both ways as she peers into the hallway. She lurches out of her apartment, slamming the door behind her. Dashes to the emergency stairwell. Throws open the door to find -- The Unusually Tall Woman. She towers over Clara, blocking any chance of escape.
The above scene heading could also be written as follows:
INT. OUTSIDE CLARA'S APARTMENT - HALLWAY - DAY
Does that all make sense, or does your brain now hurt in a bad way? Let me know!