Originally Posted by assm0de
Is it possible that reducing the RGB bias in the service menu has reduced your peak white? Why would you do that anyway? I read someone else did that too, what is the benefit? Mine are at around 132-137 by default, I guess they set them at the factory that way.
Because when your ADC is calibrated optimally (the full HDMI input range is mapped to the full video processor range without clipping or reserving any values on any sides) then single-color gradients will suffer if you either set any RGB-Gains above 128 or the Contrast above 95 (or [M]SubContrast above 128).
I already suffered from this color gradient clipping with full factory default Movie mode settings (and I believe all of you do). The workaround was to reduce the Contrast until I clipped back all the single channel ranges to the point where the white point didn't suffer anymore.
I tried to minimize the number of the requisitioned controls and use the optimal one from the numerous redundant options.
I believe this is the optimal solution. I carried out the gray-scale calibration using 2 Base WP Gains and the 10p system, and my gradient is smooth (instead of using the Base WP controls semi-randomly and then cut everything back with [M]SubContrast -> Another problem that Movie mode has it's own SubContrast setting, so different picture modes aren't in sync with the conventional method unless you set them up separately with Contrast and/or [M]SubContrast.)
Peak brightness is indeed higher with higher RGB Gain values but both single-color and gray gradients suffer from clipping (unless you reduce the Contrast/[M]SubContrast but then you reduce the peak brightness again - probably even further if you use the less precise Contrast control and you also set it one notch lower than required because you don't trust in your subjective judgment about the near-white clipping -> this method is exact, you don't need to judge anything subjectively or fear about clipping, it's nice and easy...).
Side-note: As a PC user, I use the full 0-255 range. The clipping of the single-channel ranges is less noticeable with 16-235 TV levels input because the damaged range is fully or partially located in the Whiter-Than-White range (which you shouldn't really care about with TV levels).
But even if all your inputs are 16-235, I believe this method is still more exact and safe (again, you need to judge about the clipping subjectively if you decide to cause damage in the near-white [in this case near-whiter-than-white