I think this is a difficult concept for people because our brains do such a good job compensating for mixed lighting. Our built in auto-white balance is too goo

I think this is a difficult concept for people because our brains do such a good job compensating for mixed lighting. Our built in auto-white balance is too good. One example I use to explain this is the classic Hollywood 'moonlight' trick, which is achieved by using a daylight balanced source like a large HMI, and then using film or a camera that is balanced for tungsten. Looks like daytime to the eye, but on camera it looks like moonlight. There are even special gels just for correcting various light sources CTO (color temp orange) CTB (color temp blue) and minus green (correct gross flo lights). The rest are usually regarded as 'party colors' since they are for non-technical corrections.