RGB SMT LED Cube, resistors, drivers, and shift registers.

Using Arduino LEDs and Multiplexing
14

You are dealing with a few things:

  1. different voltage drops causing different If for the same resistors. In your example, your reds have about 2.1v voltage drop and your greens about 2.8v. So to achieve desired If, the reds need to have resistors of (3.3v - 2.1v) / If and (3.3v - 2.8v) / If for the greens.
  2. even if the same If goes through all leds, they have different efficiency / light output and our eyes have different sensitivity to different colors.

So play around with different resistors until your eyes perceive them to have same brightness. No point in having very precise values for those resistors.