Originally Posted by randal_r
To answer the need to know the make and model; it is important. Each manufacturers and models have different idiosyncrasies. With Sharp, their displays push about 9000 K ~ 10000 K white point out of the box. Many professionals have had difficulty setting the D65. Most of the time the best that is achieved is around 7500 K but this is not without sacrificing something along the way. It is as if Sharp had not bothered to adjust their displays from the Asian 9300 K white point standard to the REC-BT709 D65 white point standard. Others have stated that on some models the CMS features do not work as they should.
If you read posting #6 of this thread by "johnfull", you will see he states, "I have had 2 Quattrons in the last 3 years, which I have set up with the AVS calibration disc and my own perception of white point". Why did he need to create his own white point? Is it that he could not achieve D65?
Your statement, "Sharp Aquos Quattron LC-70LE847U...although I can't imagine why that would affect the answers. Do the principles of calibration change from display to display? Wouldn't that be like the laws of physics changing from city to city"? Yes, it does effect the answer. The principles of calibration do not change, it is dealing with the quarks of the display to achieve the desired settings of a calibration this makes it more difficult. No the laws of physics still apply from city to city. Many better than you or I would opt out for option #4 from the option list from the first posting. If I were doing such a display, I too would probably settle for #4 .
Quattron utilizes a wavelength range that RGB equipment is not
able to properly read or incorporate into formulae.
Several people have tried to calibrate a white point with SpectraCal
and ended up with the same yellow/green white as each other.
There is something fundamentally wrong with calibrating a RGBY
screen using RGB tools -- the Y is ignored and the amount of blue
needed to counteract it is thought to be excess. Does this make
sense? I used the calibration disc to get a clean white and then'
fine-tuned it to properly bias the chroma signal for decent fleshtones.
The guys with the software and colorimeters have not been kind to
my efforts, but others who own these sets have been very appreciative. The quirks of the Quattron system can be tamed, but
not by traditional calibration methods, unfortunately.
Same can be said of Quantum Dots, which are proving to give false
readings on last year's Sony Triluminous models.
My hunch is that the royal blue LED that supplies the blue primary
and energizes the phosphors/dots of red and green (and yellow) is
not an ideal blue to begin with. Most problems have been coming
from the attempt to compensate for a very cold indigo/blue in making
blue/greens and cyans. Sony actually used a bluer shade of green!
Sharp was going to make a wide gamut with Quattron, but that
blue has scotched the idea of opening up the middle at all.
Instead, they have had to retreat to using the yellow merely as a
counteracting element to the miserable blue. It makes for brightness,
but the original promise of tropical blues is dead for now.
So is Quattron dead for now in their new 4K sets.
Maybe a better backlight will come along to make a truly wide gamut
possible and then Quattron yellow can allow a deeper green as well.