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A new tool for owners of 4K/UHD/HDR televisions and projectors has been announced! I have been collaborating with Ryan Masciola, of Diversified Video Solutions, LLC., producer of the UHD/HDR10 display calibration program, for the substantial revision of his suite of test patterns and a soon forthcoming revised version of his 4K Blu-ray Disc.

I purchased and have been using his versatile calibration program for some time. One thing I noticed it lacked was any test pattern for adjusting ambient lighting in the video viewing environment or any instructions for this critical element in properly setting up any video system. His revised program will now include these important features, along with attribution for my participation. This program and disc will be must-have tools for anyone with 4K displays in order to adjust and calibrate them for optimum performance. Here's a link to his announcement of the details:

https://www.avsforum.com/forum/139-display-calibration/2463698-r-masciola-s-hdr-10-uhd-test-patterns-48.html#post56567478

Here is the preliminary information I submitted to Ryan for inclusion in the program's instruction manual:

"General Information About The Ambient Light Level Visual Comparison Patterns

These patterns offer a means to adjust ambient lighting (aka: bias lighting) on the wall behind the display via a visual comparison to the brightness of the various windows. Many users of this program will not have access to a spot photometer or suitable spectroradiometer to measure the luminance on the wall.

The study of human visual perception is at the foundation of the video medium. Human vision is the basis of imaging science and technologies that seek to produce artificial images. Ambient lighting and surrounding colors in the viewing environment affect how the viewer perceives the image on a TV screen or electronic monitor. An otherwise "perfectly" calibrated display cannot deliver a reference image to the viewer in a non-reference environment. Video industry standards bodies (SMPTE, ITU, EBU, ATSC, etc.) and video engineers have understood these principles for over a half century.

A 'Reference Viewing Environment' has been specified to include a neutral gray "surround" and low level back lighting that is CIE D65 (aka: 6505K CCT) behind the monitor for decades. The room is to be devoid of any substantial additional lighting. These reference conditions are designed to minimize screen reflections, haze, and glare, plus relieve eye strain and preserve accurate color perception. All of the current display calibration specifications are taken from the standards and best practices used in the professional mastering of video programs. Such standards and best practices are used throughout the industry to insure consistent and unified program production, post-production, and program reproduction (image fidelity).

This UHD/HDR10 calibration program is primarily intended for the newest video displays. The most recent revision of reference viewing environment standards and recommended practice by the Society of Motion Picture and Television Engineers (SMPTE) specifies a formal standard of an ambient light level of 5 nits (cd/m2). This is also the most recent recommended practice specified for HDR imaging by the International Telecommunications Union (ITU). Both of these standards bodies specify the display to be calibrated to 100 nits for peak white, using a specific sized window pattern. The ambient light level visual comparison patterns in this program have 5, 10, and 15 nit windows derived from the formula for calculating the electrical optical transfer function (EOTF}, or Perceptual Quantizer Transfer Function (PQ), for HDR (SMPTE ST 2084:2014). The 10 and 15 nit window patterns are for comparison with older recommended practice as noted in the patterns.

How to use the patterns:
Simply display the pattern of choice after calibrating the display while visually adjusting the ambient lighting on the wall behind the display in an otherwise light-less room. Visually compare the level of light on the wall to the level of light in the window. PLUGE patterns are included with the window for tweaking the black level (aka: brightness) of the display with the ambient light present. This is to insure the adequate perception of shadow detail in the final image.

For additional study of viewing environment principles, practices, and solutions, see this technical document: https://cinemaquestinc.com/ive.htm , plus the standards documents referenced."

Formal standard of 5 nits (cd/m2) SMPTE ST 2080-3:2017 'Reference Viewing Environment for Evaluation of HDTV Images;' ITU-R BT.2100-0-(07/2016) 'Image parameter values for high dynamic range television for use in production and international programme exchange,' recommended practice for HDR

Recommended practice of 10% of a peak white at 100 nits (cd/m2); SMPTE RP 166-1995 'Critical Viewing Conditions for Evaluation of Color Television Pictures,' for SDTV; ITU-R BT.2035 (07/2013) 'A reference viewing environment for evaluation of HDTV program material or completed programmes,'

Recommended practice of 15% of a peak white at 150-250 nits (cd/m2); ITU-R BT.710-4 (11/98) 'Subjective assessment methods for image quality in high-definition television,' for consumer HDTV environments

Best regards and beautiful pictures,
Alan Brown, President
CinemaQuest, Inc.
www.cinemaquestinc.com
Two decades of viewing environment excellence, education and solutions, developers of Ideal-Lume bias lighting
SMPTE, THX, ISF, Lion AV Consultants

"Advancing the art and science of electronic imaging"
 
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