I haven't designed any film studios, so I can't speak to the magnitude
you should expect, but I've run across theatrical/heavy retail
situations wherein transformers for low-voltage lighting are grouped
into a remote enclosure located in a utility/data closet - those would
be a significant load that you might call a lighting/process load, even
if there aren't any lights explicitly in that closet - that's where a
large fraction of the heat would be generated/dissipated...

For further reading - an example provider of the equipment I'm talking
about is qtran: http://www.q-tran.com/

NICK CATON, E.I.T.