samueladammartin wrote:I suppose maybe color cast is not what I'm seeing but rather the colors with standard display transforms from Blackmagic are yielding unnatural (To my eye) results.
No camera in the world sees all colors exactly like you perceive them, please read about metamerism.
Natural light is still the best, but it changes massively over the day, with humidity in the air, and your elevation over sea level. That's what we have WB for. Tungsten is second best, but it generates more heat than light.
Modern lamps, based on fluorescence or LED, are very bad when they are cheap ones for general use, like the ones in parking areas. Sodium vapour lamps, which are used a lot these days for traffic areas, even have only one color out of the whole spectrum.
If you want practicals in your scene, check the carefully and change if needed. Only use those made for filming with a good color rendition value and switch off the rest. It can be very difficult to correct for color shifts caused by light sources which don't emit the full spectrum.
P.S. Don't blame your camera, BM's color science is one of the best.