That's a good question...
I guess the final product, as shown on stage, has everything in place and that includes wardrobe, make up and of course, lighting. In those moments the colours are a critical part of the message. It has been thought about, created and balanced so I thing part of my job is to catch and represent those too.
Rehearsals and creation are a different beast altogether. Fleeting moments that may never happen again. I'm always on he hunt...but the space, the clothing, the lighting and any and every serendipity object is, more often than not, detracting or distracting. In those moments, i usually prefer the black and white attention to detail.
I may also just by bias or use to it, who knows
I hope this makes a little sense out of my head.
Thanks for asking