Don't think this one's been covered before, but apologies if it has.

This week I've been shooting a show in a small theatre, and I've used slightly tweaked tungsten WB settings to match, as far as possible, 4 different cameras (yes, I know that's asking for trouble but that's how it had to be). It was a live mix to hard drive each night.

The matching worked surprisingly well with the colours coming across convincingly, but I had an unexpected problem with images projected as part of the set from a data projector. Some of the colours used in the projected images were pretty far out eg purple recorded as light blue but the rest seemed fine. I can understand why the data projector lamp would be at a different colour temperature from the theatre lights, but not why only some colours seem to be affected. It looked very odd in the camera monitors, epecially on the Canon XH-A1 which was used to capture the projected images at scene changes.

Has anyone else come across this or can anyone suggest a solution?

I don't have an answer for this, just an observation. I recently taped a presentation that used a projector for projecting video as well as power point slides. Part of the time I would have the camera on the projection. Occasionally the colors would start to change - like a color wheel was on the projector - . What was strange is that it didn't happen all the time just occasionally. Didn't bother me though as I had arranged to get copies of both the videos and PP to insert in post. Just strange.