This is a method I discovered by accidentally adjusting contrast and brightness and seeing that these parameters have an effect on rgb levels during continuous measurements. Instead of focussing primarily on rgb levels at each window ire interval, I concentrated on what would be the best contrast and brightness level for my hdtv that would allow rgb levels close to 100 % from 30 ire to 80 ire. The reason that I call it the sweep method is simply sweeping or raising/lowering the contrast or brightness levels to produce consistent rgb levels across the grayscale.
I just calibrated my Samsung PN50b450 by using hcfr software and xrite eyeone lite and gamma response is pretty level. I have been DIY calibrating for over two years. Recently, I initially started using the HD DVE disc with the red/green/blue levels even at 100% at 80 ire. I then noticed the other rgb levels at 50, 60, and 70 were not level but were greatly affected when adjusting the contrast and brightness levels. I kept adjusting the rgb levels at from 50 to 80 ire by using the contrast/brightness controls, and later separately rgb levels from 30 to 40 ire, until all rgb levels of the greyscale from 30 to 80 consistently came within 2 percent of 100% levels. This made my gamma a straight flat line and a terrific picture. My highest delta E is 2.5.
I think that all hdtv's have a sweet spot which can be found by adjusting (slowly but surely) the contrast and brightness settings to where rgb levels are consistent between 30 and 80 ire. For example, if your 70 ire has a red level at 95%, adjusting the constrast or brightness may raise this level while not affecting the 80 ire rgb levels. After I completed my adjustments, my 100 ire had a measurement of 40.8 ftL and the 10 ire was exactly .65% of the 100 ire, which may be perfect.
I call this the "sweep" method and it primarily involved adjusting the contrast and brightness levels and a lot of trial and error. See the images below for the gamma and rgb graphs.
The cell light was originally set at 10 - as recommended for this display, but readjusted to 9 to level out a bump in the gamma graph. I also attempted to lower the cell to 8 but the gamma graph just went bonkers.
The following are my settings for a dark room setting. The resulting gamma was 2.36 (the hcfr gamma setting preference @ 2.4 for dark room environment), with static contrast at 1173:
color space auto
offset: red 29, green 25, blue 35
gain: red 25, green 25, blue 45
hdmi black level low
all options off
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