movie projector color balance

JB Earl · November 22, 2013

I never really thought about this in detail, but if you we're shooting an outdoor scene at dusk (after sunset) involving a projected movie in the background, what would you balance for? Small projectors of course are tungsten, but what about big screen? How would you choose to balance between the very cold ambient light and the tungsten projected image (unless big projectors are daylight balanced?)

My feeling is to let the ambient be mostly proper, but I'd hate to have a really yellow glowing image in the background.

Tim Tyler · November 22, 2013

You could research the make and model of projector being used to find out what its color temp options are.

You could also project a known white image from that projector onto a white card and then white-balance your camera to see what the color temperature result is.

You could also use any digital still camera with raw capability to photograph any projected image on the screen. Ingest the raw photo into software like Lightroom and drag the "color temperature" slider back and forth until the photo looks proper. Note the value of the color temp slider.

Once you know the color temperature you could try filtering the projector lens in order to match the projector's output to your preferred color temperature. Filtering the projection will reduce the output intensity.

David Mullen ASC · November 23, 2013

Most big projectors in theaters, 35mm and digital, use xenon light (slightly more blue than daylight balanced). A long time ago, theaters used carbon arcs (closer match to daylight than xenon).

JB Earl · November 23, 2013

that will certainly solve my problem. I'm rough storyboarding something at a drive in.

thanks much

Info from Tim also put in my mind some ideas with scenes with a small projector outside, like they used to do at summer camps

Bruce Greene · November 23, 2013

A while back I shot I scene at a drive in theater. We used a 16mm projector, with a print borrowed from the local library as a key light on the actors. Today, I would do a reverse of the screen as a digital effect shot.