You should use 0's for red and green, but 1 for blue - it's the absolute closest you can get to black without being black. Having it exactly black (all zeros) seems to cause strange things to happen when outside (try it once and see what happens - things can look very weird). If using 16-bit color instead of 32-bit color, then you'd set blue to 8 instead, again the absolute closest possible. I have all the numbers and I've run many tests to verify this.