I've been split filtering under a "looks white" Zone VI cold light; I get normal contrast with normal negatives at about equal exposures of the blue and yellow filters. I'm using Lee theatrical filters, the 100 Spring Yellow and 119 Dark Blue (I wanted 795 Magic Magenta, but they didn't have it locally and ordering it in would have cost too much and taken too long for my needs). Bonus: two "half sheets" of this material cost about $15 plus the gas to pick them up, and each 20x24 inch half sheet is enough to make twelve 6x6 inch filters, or forty-eight 3x3 size.