I shot a group of people with different skin tones. How do I brighten those with dark skin tones without affecting the others ? Which FX would result in a balanced look ?
Why would you want to? Is the video either under or over exposed? If yes, then correct that and the skin tones will fix themselves. In short fix the black and white point, (shadows and highlights) then the midtones should be very close, then you can tinker with color corrector for the mid levels and/or color curves and a whole host of other tricks. I know a little about the topic. :-)