What do integrators need to know about wide color gamut displays and content?
Distinguishing WCG from non-WCG
The color gamut of a display is usually quantified in terms of the NTSC standard created in 1953. Most LCD displays on the market today are designed to meet the HDTV color gamut standard, known as Rec. 709 (or alternatively BT.709). Compared to the NTSC standard, the Rec. 709 color gamut covers roughly 72% of the NTSC color gamut. In display circles, we refer to the color gamut of a display using this percentage NTSC measurement, such as “72% NTSC,” which is the most common specification for LCD displays on the market.
While there’s no formal definition for wide color gamut (WCG), anything above 72% NTSC is generally considered to be WCG, and anything at 72% or below is non-WCG.
WCG display technology
We’ve seen many classes of WCG displays released in the last few years. Many displays are reaching 88% NTSC, 98% NTSC and even higher. Some of these wider gamuts are achieved with improved backlight technologies, though they have finite limits of the color gamuts that can be reached. Newer display technologies such as OLED, quantum dots, and direct view LED can easily exceed 100% NTSC.
The ultimate goal is to achieve the Rec. 2020 (or alternatively BT.2020) color gamut, which is roughly 150% NTSC. This covers more than three-quarters of the visible color spectrum, allowing for amazing colors never before seen on a display. Expect displays to start approaching Rec. 2020 as the decade progresses.
So WCG is better, right?
Not necessarily. Most content is recorded assuming that it will be played back on a Rec. 709 display. A display with a wider gamut will display these colors incorrectly, which can make the content look unnatural. Some people may prefer to see the colors displayed in a more saturated manner, though in many cases this can lead to people looking sunburned or objects appearing cartoonish, for example. Having the ability to perform color correction is essential for ensuring that the display is setup appropriately for the content to be shown.
LED displays utilize wide color gamuts for more vibrant color performance.
Just as there’s very little 4K content, there’s also very little WCG content. The first widely distributed WCG content will be UHD Blu-ray, which will be encoded in Rec. 2020 format. Expect to see more WCG content as we see an expansion of 4K content distribution.
Special thanks to my colleagues Marques Girardelli and Jeremy Sternhagen for providing this insight.