rear projection

[Tyler JohnsonWilliams]

Hey, I'm gaffing a project and the DP wants to do a rear projection thing for the project. It's the classic make a car look like it's driving while it isn't scenario. I'm on the side that a green screen would be easier but he wants to try this first. Any tips or tricks for rear projection would help a bunch.

Thanks

[Kevin W Wilson]

I agree, a green screen would be easier and probably a bit less of a headache. Not to mention giving you more control in post over what your final background will look like. With rear projection you will need to shoot your background plates first and reverse them for projection through a two way screen. Lighting for rear projection tends to involve a little more thought because the more light that spills to the screen the more washed out your background will look.

 

There's several older issues of Cinefex that have articles with breakdowns on how this effect is accomplished, research goes a long way into the success of any effect. James Cameron's films would also be a good place to reference, The Abyss, Aliens and Terminator 2 all used rear projection pretty extensively.

 

Andrew Lazlo's book, Every Frame A Rembrandt, has a pretty good explanation of how he had to scrape together a scene for the first Rambo film very last minute, and I believe he used rear screen projection and some simple rotating canvas paintings to do it. It's also a wonderful book from a veteran of the craft, highly recommended.

[John Sprung]

Are you shooting film or digital? Projecting film or digital?

 

In the old days, they'd take the shutters out of the projectors so as not to lose any light to the interrupt blade. With selsyn motors, the 180 degree camera shutter would reliably cover the 90 degree projector pulldown. They'd rotate the whole projector motor to get that lined up right. With digital, you'd want to have some equivalent kind of sync and phase adjustment and lock to be sure that each frame you shoot gets exactly one frame of the plate. With film, they always had several prints of the plate, in case it got damaged.

 

 

 

 

 

-- J.S.

[Paul Bruening]

Are you shooting film or digital? Projecting film or digital?

 

In the old days, they'd take the shutters out of the projectors so as not to lose any light to the interrupt blade. With selsyn motors, the 180 degree camera shutter would reliably cover the 90 degree projector pulldown. They'd rotate the whole projector motor to get that lined up right. With digital, you'd want to have some equivalent kind of sync and phase adjustment and lock to be sure that each frame you shoot gets exactly one frame of the plate. With film, they always had several prints of the plate, in case it got damaged.

 

 

 

 

 

-- J.S.

 

Weren't the cam and projector mechanically linked back in the H-wood hey days? Did that ever change to electronic sync or are all those old process set-ups still mechanical?

[Tyler JohnsonWilliams]

Thanks for the tips. I read the Every Frame a Rembrant book, and the gag is awesome but this will be inside a vehicle looking out. I really want to try that rotating canvas set up though. We're shooting on the RED but it sounds like it will be way simpler just to green screen it.

Thanks for the help.

[Leo Anthony Vale]

Weren't the cam and projector mechanically linked back in the H-wood hey days? Did that ever change to electronic sync or are all those old process set-ups still mechanical?

 

They were electronically synced using 3-phase sel-syn motors. That's self synchronising motors. Sound was synced the same way until tape, Nazi technology, was introduced.