These are some very kind and inter­est­ing words recant­ing Heath Ledger’s on set aura, as told by Chris Nolan (via Newsweek)

One night, as I’m stand­ing on LaSalle Street in Chicago, try­ing to line up a shot for “The Dark Knight,” a pro­duc­tion assis­tant skate­boards into my line of sight. Silently, I curse the moment that Heath first skated onto our set in full char­ac­ter makeup. I’d fret­ted about the reac­tion of Bat­man fans to a skate­board­ing Joker, but the actual result was a pro­lif­er­a­tion of skate­boards among the younger crew mem­bers. If you’d asked those kids why they had cho­sen to bring their boards to work, they would have answered hon­estly that they didn’t know. That’s real charisma—as invis­i­ble and nat­ural as grav­ity. That’s what Heath had.

Heath was burst­ing with cre­ativ­ity. It was in his every ges­ture. He once told me that he liked to wait between jobs until he was cre­atively hun­gry. Until he needed it again. He brought that atti­tude to our set every day. There aren’t many actors who can make you feel ashamed of how often you com­plain about doing the best job in the world. Heath was one of them.

One time he and another actor were shoot­ing a com­plex scene. We had two days to shoot it, and at the end of the first day, they’d really found some­thing and Heath was wor­ried that he might not have it if we stopped. He wanted to carry on and fin­ish. It’s tough to ask the crew to work late when we all know there’s plenty of time to fin­ish the next day. But every­one seemed to under­stand that Heath had some­thing spe­cial and that we had to cap­ture it before it dis­ap­peared. Months later, I learned that as Heath left the set that night, he qui­etly thanked each crew mem­ber for work­ing late. Qui­etly. Not try­ing to make a point, just grate­ful for the chance to cre­ate that they’d given him.

Those nights on the streets of Chicago were filled with stunts. These can be bor­ing times for an actor, but Heath was fas­ci­nated, eagerly accept­ing our invi­ta­tion to ride in the cam­era car as we chased vehi­cles through movie traffic—not just for the thrill ride, but to be a part of it. Of every­thing. He’d brought his lap­top along in the car, and we had a high-speed screen­ing of two of his works-in-progress: short films he’d made that were excit­ing and haunt­ing. Their exu­ber­ance made me feel jaded and leaden. I’ve never felt as old as I did watch­ing Heath explore his tal­ents. That night I made him an offer—knowing he wouldn’t take me up on it—that he should feel free to come by the set when he had a night off so he could see what we were up to.

When you get into the edit suite after shoot­ing a movie, you feel a respon­si­bil­ity to an actor who has trusted you, and Heath gave us every­thing. As we started my cut, I would won­der about each take we chose, each trim we made. I would visu­al­ize the screen­ing where we’d have to show him the fin­ished film—sitting three or four rows behind him, watch­ing the move­ments of his head for clues to what he was think­ing about what we’d done with all that he’d given us. Now that screen­ing will never be real. I see him every day in my edit suite. I study his face, his voice. And I miss him terribly.

Back on LaSalle Street, I turn to my assis­tant direc­tor and I tell him to clear the skate­board­ing kid out of my line of sight when I realize—it’s Heath, woolly hat pulled low over his eyes, here on his night off to take me up on my offer. I can’t help but smile.