faint background colors differ

[maineventer]

Hello, I shoot stage photography where grayscale banners are often hung along the back of the stage and are lit different colors by lighting. The lighting on the banners is dimmer than stage lighting itself. In person the eye can see purple banners but in photos they appear dark aqua. Red lit banners can be seen by the eye but are almost non existent in photos. Other colors do this as well. Any idea what causes this? I do a white balance for stage lighting and subjects on stage look fine. It's just the banners in the background that appear different in photos from what they look like on stage to the human eye.

Thanks,
Matt

 

[TCampbell]

White balance only works when all the light is the same type and color temperature. Unless the stage only has one type and color light operating at a time and doesn't change throughout the show, you can't really white balance for it.

If you white balance for subjects on stage, but the banners are lit by different lights (not the same color temperature) then the white balance for the subjects wouldn't apply to the banners.

 

[Tony S]

In addition to the above it's also probably because those background banners are not lit as bright as the stage lights, so your dynamic range is too great to get the colors as the eye sees them(which picks up a huge dynamic range). Just too much of an exposure difference between the two areas that are lit.

 

[KmH]

The issue Tony is referring to is also about the Inverse Square Law. Being further away, less light from the background reaches the camera.

 

[bratkinson]

Although I have zero experience in such a situation, I think I'd try taking a couple shots of the banners preceeded by a grey card shot or two held up in front of them for white balance. Then shoot the rest of the show with WB set for the front part of the stage.

Step two would be in post...separate out the banners into another layer, set the WB on them, then merge the layer back into the original photos.

Maybe I'm off in left field, but it might be worth a shot.