Ambient background bias lighting - does it make a difference?

[Alan Brown]

There are now new models of Ideal-Lume bias lights in LED! http://cinemaquestinc.com/ideal_lumesb.htm#LEDStandard

Best regards and beautiful pictures,
Alan Brown, President
CinemaQuest, Inc.
SMPTE, THX, ISF, Lion AV Consultants

"Advancing the art and science of electronic imaging"

[VeryNew]

Where can i purchase ideal-lume in Vancouver bc?

[Alan Brown]

You will have to order it from the company's online store. Distribution is direct to consumer only.

[Alan Brown]

https://forum.blu-ray.com/showpost.p...96&postcount=1

[youngsyp]

Originally Posted by Alan Brown

https://forum.blu-ray.com/showpost.p...96&postcount=1

The page on the end of that link doesn't really tell us much. However, these 'reference viewing environments' aren't complex. They are essentially as follows:

HD/ SDR: a pitch black room with a D65 bias light of 10% of the displays peak white output (measured as a reflection from the surface behind the TV).


HDR/ DV/ HLG: a pitch black room with a D65 bias light set at 5 nits (measured as a reflection from the surface behind the TV).

There's some mention of 'ambient' lighting for the former but, the light from the bias light would boost ambient light levels, so it's arguable whether any further 'ambient' lighting would be required.

Paul

[Alan Brown]

Originally Posted by youngsyp

The page on the end of that link doesn't really tell us much. However, these 'reference viewing environments' aren't complex. They are essentially as follows:

HD/ SDR: a pitch black room with a D65 bias light of 10% of the displays peak white output (measured as a reflection from the surface behind the TV).


HDR/ DV/ HLG: a pitch black room with a D65 bias light set at 5 nits (measured as a reflection from the surface behind the TV).

There's some mention of 'ambient' lighting for the former but, the light from the bias light would boost ambient light levels, so it's arguable whether any further 'ambient' lighting would be required.

Paul

Your attempt at summarizing the current SMPTE formal standard and recommended practice for a "reference viewing environment" isn't quite accurate. The published document on the issue is more complex than you allude to. I suggest obtaining the actual document from SMPTE.org or re-reading it if you already have it.

One obvious item of departure from your post is made clear in the actual title of the SMPTE standard document referenced from the link. The new formal standard of 5 nits ambient light level applies to HDTV viewing environments in program mastering applications. The former 10% of peak white recommendation has been around since the days of the NTSC SD CRT monitors. An updated revision to the former 1995 SMPTE document was long overdue and requested by many for years.

A 10% or even as high as 15% recommendation in consumer video environments might still be appropriate for any direct-view display type. The most aggravating cause of viewing fatigue from video use is the frequent and random fluctuation in scene brightness during motion programs. Mastering technicians have estimated they view still images around 50% of the time.

Providing a "pitch black" room is not required in video post-production suites. There is always some minimal stray light present from nearby grading software and signal analysis monitors, as well as backlit keyboards and occasional down-firing task lighting for the control console. There are specific tolerances recommended for how much light is allowed to strike the program monitor screen. Numerous other specifications and recommendations pertaining to additional aspects of the viewing environment are discussed in the document.

Here is a link to order a PDF of the SMPTE document titled 'ST 2080-3:2017 - SMPTE Standard - Reference Viewing Environment for Evaluation of HDTV Images':

https://ieeexplore.ieee.org/document/7918583

Best regards and beautiful pictures,
Alan Brown, President
CinemaQuest, Inc.
SMPTE, Professional Video Alliance, THX, ISF, Lion AV Consultants

"Advancing the art and science of electronic imaging"

[Alan Brown]

ITU-R Recommendation BT.2035 : "A reference viewing environment for evaluation of HDTV program material or completed programmes"

https://www.itu.int/rec/R-REC-BT.2035-0-201307-I/en

Best regards and beautiful pictures,
Alan Brown, President
CinemaQuest, Inc.
SMPTE, PVA, THX, ISF, Lion AV Consultants

"Advancing the art and science of electronic imaging"