Colour theory in lighting

[Leon Brehony]

Hello all,

I've got a lighting challenge that I'm unsure about. I'm shooting a commercial on a small studio set with a solid blue backdrop and one 'character'.

For the opening I want to have a spot on the backdrop which silhouettes the character, before the spot gets killed and the main lighting for the rest of the ad faded up.

My question is - in an attempt to get a solid white spotlight on a primary blue backdrop is it as simple as picking a 'complimentary' colour for the spotlight, e.g. yellow/red?

Trying to apply some basic colour theory stuff which I've been reading up on but not put into practice too much yet.

I'm unsure about the ability to achieve this effect in post as the character is also being lit by a dim blue light from a laptop/tablet whilst the white spot silhouettes them.

Cheers!

[Mark Dunn]

I don't think the mixing idea will work as you're combining reflective and transmissive colours. You would just get a yellow/red tinted blue.

Just make sure that the white spot is bright enough to read as white on the background.

[David Mullen ASC]

You could try a yellow spot to neutralize the blue but the truth is that white requires overexposure of the blue backdrop so it's more important that the spot be bright enough -- if it burns out to white then it doesn't really matter what color the light or the drop is.

The other option is to use a pale blue drop and light it with deep blue lighting to make it bluer, then the bright spot will go white faster. Or even use a gray drop lit deep blue as long as you can keep all other ambient light off of it.