For Professional ISF Calibrators, Gamma adjustments in HDTVs and UHDTVs are useful tools we use every day when we match TV light output to various room lighting conditions. For end users, the term Gamma in their TV screen menu’s is both meaningless and confusing. This situation is now improved for professionals, but will be even more confusing for end users.
Since the 1930’s, the way old tube (CRT) TVs made pictures from TV signals had been the model for all TV engineering, both professional and consumer. Mimicking a tube was far from a precise science, but that was the accepted practice since the dawn of solid state TV technologies like Plasma, LCD, DLPs, LCoS and OLED. In Geneva in 2008, the European Broadcast Union issued a recommendation of “approximately” 2.35 as a recommendation for professional monitors. That was at least a useful step in getting professional monitors to go beyond tube TV characteristics
A Warm Welcome from the ISF to ITU BT.1886 EOTF
Thankfully, in 2011 the International Telecommunication Union issued a formal recommendation based on solid state, not CRT, TVs. In that 2011 document, gamma nomenclature was redefined, and finally after 80 years actually specified! The new name is EOTF, an acronym for “Electro Optical Transfer Function”. That will be completely incomprehensible to end users, and is aimed at us professionals.
The new response curve is based on digital monitor characteristics, not tube TVs. It does not have a traditional numeric designation and is simply called BT.1886. It is close to what we knew as gamma 2.4, with a difference in the curve in the dark areas of images. Even professional monitors took a few years to begin to evolve to this new EOTF, and thankfully current progress in content creation adoption is accelerating. Many professional monitors already default to BT.1886 so content will be created this way.
What does that mean to calibrators? Guesswork on gamma selection in controlled lighting conditions is now a thing of the past. In studio like lighting, simply set your calibration software to BT.1886 and get as close to that as the TV permits. In bright rooms, your judgment is still needed to match TV light to room light.
ISF Congratulates Panasonic and LG
In Amsterdam March 2014, I had the pleasure of announcing to European press conferences that Panasonic was the first consumer television manufacturer I know of to include BT.1886 in TV designs in their “Professional” modes. In April 2014, LG Picture Quality Labs in Seoul emailed that they will also aim for BT.1886 compliance in their upcoming new model’s “High” gamma mode. In both Panasonic and LG TVs, their multipoint gamma tools can fine tune the factory work to insure our client’s TV are precisely BT.1886 compliant. In many other brands, we can also get close to compliance with mode selections and multipoint gamma tools. I expect additional manufacturers aim for BT.1886 compliance shortly. The press is helping drive this transition as well. CNET is already testing compliance in TV reviews, and Home Theater Review just covered BT.1886 online. We had coverage of this in multiple European and UK articles. This is superb progress in these early days! The ITU document is public domain and is available at: http://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.1886-0-201103-I!!PDF-E.pdf
ISF Calibrators Take a Leadership Role in BT.1886 Adoption
With our fantastic geographical coverage, ISF’s thousands of calibrators can immediately provide great service to their clients with BT.1886 compliance, as well as bring awareness of this new “Language of Light” to the public. This is just one small step on the road to UHD advances that we will be bringing to your attention. Expect UHD to eventually bring us better motion, better colors, better shades of color, and perhaps high dynamic range, as well as the improved resolution and EOTF that we are already enjoying today.