Here is a defining quote from the introduction to the SMPTE Standard document:
"The creation of television images that are intended to follow a standard of consistency in reproduction requires definition of a reference display, of a controlled viewing environment, and of a set of measurement...
Here is a link to a free PDF of the SMPTE standard document that discusses reference viewing environment conditions for video:
SMPTE ST 2080-3:2017 "Reference Viewing Environment
for Evaluation of HDTV Images"
https://ieeexplore.ieee.org/stamp/st...number=7918583
Here is a link for the...