Originally Posted by Otto Pylot
Both of those articles are excellent for understanding the why's and wherefore's of bias lighting, albeit a bit technical for the uninitiated. The simple
answer is a neutrally colored wall behind the tv with a light source as close to 6500k (accurately measured) as is possible.
Day and night calibration is a different matter so I'll let the professionals detail that one. Some folks seem to get by with one calibration and just change the backlighting a bit to compensate for the changing room conditions but it depends on what your room conditions are to start with. Vague I know, but....
Unfortunately, your "simple" answer leaves out critical information such as:
"Neutral" must be understood in video industry terms, not interior design terms. Interior designers will refer to all "earth tones" as neutrals. The recommended "neutral" color for display surrounds is that which reflects all colors equally (shades of gray, including white).
The light source must also be located behind the TV, so that it is not directly visible to the viewer, so that it "washes" the wall with illumination. This is necessary in order to avoid light reflecting off of the TV's screen.
The amount of illumination reflected from the wall is recommended to be about 10% of the brightest white the TV produces after it has been calibrated for dark viewing conditions.
It should be mentioned that so-called "day" and "night" calibration modes do not eliminate viewing environment problems. Any "day" mode cannot completely correct for the consequences of high ambient room lighting, or conflicting colors in the area surrounding the TV screen (within the observer's field of view). All a "day" mode can do is partially compensate for conflicting viewing conditions. Only a "night" mode has any chance of delivering a reference viewing experience.