Exploring 4K: Does Color Trump Resolution?
Video expert Joel Silver explains why 4K is a piece of the puzzle, but not the next-generation standard bearer for high-performance video.
Robert Archer · November 11, 2014
Ever since the failure of 3D as a long-term movie and TV sales driver, both Hollywood and the consumer electronics industries have determined that 4K, or Ultra HD, provides the best opportunity to drive video product sales.
Since both industries began to focus on 4K, momentum for the format has been steadily gaining steam. Highlighting that momentum was the buzz it generated at two of the biggest tradeshows of the year — CES and InfoComm.
Both events featured a number of 4K products and the interest for the format on each respective show floor was noteworthy.
Taking a step back from all of the 4K enthusiasm is Joel Silver, president of the Imaging Science Foundation (ISF) and one of the A/V industry’s preeminent video experts. For well over a year, Silver has been cautioning installers that there are other fundamentals in place that should take a higher priority than resolution.
4K Part of the Larger Picture
Silver is excited for the future of video and the performance potential that exists with some of the upcoming initiatives the professional and consumer markets are working on, but he points out that 4K alone won’t push video standards into breaking new ground.
“Having 4K is one part of UHD and [next-generation, high-performance video], but it is not the most important part and people don’t get that,” says Silver. “It is part of the roadmap, and there are two flavors of 4K, which is exciting, but there is a committee looking at HDR [high dynamic range].”
The reason why HDR is so important for the next generation of video quality, Silver says, is the public has lived with the same temporal resolution since 1939. In the near future he notes — around 2017, 2018 — advances in color gamut will really drive innovation.
“Going from 2K to 4K is an improvement, but it is not revolutionary,” he admits. “But the new colors, that is something. There is a lack of understanding concerning the rollout of 4K. I would much rather have a dynamic 2K HDTV than more pixels. Something with great blacks or great HDR, that is more impactful. Resolution is only apparent when you are close.”
Underscoring what is happening in the video world, Silver emphasizes that 4K is just the first part of a new system. “Frankly [4K] is the least impressive part of the roll-out,” he boasts.
Color Space Advances Key to Quality
According to Silver, the underpublicized part of the impending video industry’s format updates is the expanded color gamut that could become a part of their final specification.
“The 2020 color space (the International Telecommunications Union Radio Communications ITU-R BT.2020 recommendation) is going to be great for laser color space, but it will be difficult for older TVs.”
“Flat-panel TVs will be expensive,” he continues. “The broadcast space already uses [the spec]. I have a 17-inch HP laptop that was part of a venture with DreamWorks and it includes Rec 709 capabilities and the Adobe Color Space that is much better than HD. The laptop also does DCI (Digital Cinema Initiatives).”
“I can in a two-minute demo show pictures in three different color spaces. Improvements in color gamut are instantaneously superior to the average viewer. Showing Adobe Color Space over Rec 709 is noticeable. Glancing at 4K, the average person doesn’t see [a noticeable difference] because it is just resolution.”
Joining manufacturers that include Digital Projection (DPI) and Sony in their enthusiasm for laser-based projectors, Silver says these products along with LED solutions will be able to deliver the color gamut capabilities that are a part of the next-generation formats.
“The Ultra HD format will bring us all of that,” he notes. “It will deliver a much better image because dynamic range is more important.”
Quality Begins With Basics
The impending video formats may offer wider color gamuts and more resolution, but just like current industry standards, their respective performance is based on the same fundamentals as current-generation formats.
Both HD and Ultra HD/4K require proper black level and contrast setups before moving onto color and resolution calibrations
“Contrast is the most important parameter,” emphasizes Silver. “If you don’t have good blacks and whites, you won’t have a good image. Some of the great engineering minds from Philips, Dolby, the BBC (British Broadcasting Corporation) and Technicolor look closely at contrast.”
Explaining further, Silver says those in the video industry, including the International Telecommunications Union (ITU), are examining ways to develop “smart” dimming where the content “directs” displays to dim.
“The question is, can they monetize the technology to include it in video displays?” he says. “Contrast remains the single most important feature in evaluating a TV.”
Backing up his statements on contrast ratio, Silver says dealers need to examine the CEA/CEDIA-CEB23-A: Home Theater Video Design specification that was updated back in 2012, which defines criteria for home theater setup and performance. It’s a good place to start when thinking about commercial installations, too.
Silver, who was a part of the expert panel that created the jointly developed the guidelines, points out the 150:1 contrast ratio checker-board pattern in CEB-23-A is unattainable for most systems, including commercial systems.
“What I aspire to when I work with home theater builders is that 150:1 contrast ratio. It is only really possible with a well-engineered room and system,” he says. “If a room has white walls, it doesn’t matter how good the screen and projector are [it won’t perform to the guidelines].”
Summing up what dealers should concentrate on as the market continues to evolve, Silver is succinct. His advice applies to designing and setting up virtually any type of flat-panel or projection system.
“Contrast is number one, secondly color saturation, and the third thing is color accuracy. The fourth thing is resolution, but it is nowhere as important as the other three items,” Silver emphasizes. “The first thing dealers should do with when presenting to clients is talk about good TVs before getting to 4K.”
“Dealers need to consider performance parameters and ask themselves when evaluating TVs, are the blacks and whites really good? Does the TV’s dynamic range give you the punch you are looking for? Can it deliver the [brightness] spec for theaters [14.4-foot lamberts (fL)]? TVs like Sharp’s Elite put out more than 20fLs. So dealers need to ask the clients if they want a good TV before they talk about 4K … I don’t worry about the market at all. The market speaks for itself, and that is why the $1,000 4K TVs aren’t doing well in the market.”
What is Adobe RGB?
A TV or projector that has the Adobe RGB color space is a key selling point for integrators to use to upgrade clients to 4K.
Adobe RGB is a standard that was first introduced in 1998 to coincide with Adobe’s launch of its Photoshop 5.0 program. Adobe says the color space adheres to International Color Consortium (ICC) guidelines.
According to Adobe, as part of an ICC-based color management system, color profiles are created for devices so colors in an image can be modified throughout the workflow process to compensate for any differences between devices.
Adobe includes its ICC profile, called the Adobe RGB color space, in all of its color managed software tools. Highlighting some of Adobe’s RGB specifications are these calibration points of interest (based on CIE Standards):
Reference White Point (CIE, 1931):
Luminance level of white displayed should be 160.00 cd/m2
Chromaticity Coordinates (CIE, 1931):
Outlining ITU-R BT.2020 Picture Characteristics
Back in August 2012, the International Telecommunications Union (ITU) Radio Communications Sector issued its rec-ommendations for the reproduction of Ultra HD content. The initiative is called ITU-R Recommendation BT.2020 (also called Rec. 2020 or simply BT.2020) and it outlines broadcast for the delivery of au-dio and video, frequency management, and time signals and frequency standard omissions.
Arguably the most important compo-nents of the ITU’s recommendation from the installer perspective are the picture spatial and picture temporal characteris-tics, as well as the trade group’s recom-mendation for system colorimetry.
Here are some of the ITU-R’s recom-mendations from its BT.2020 technology outline:
Picture Spatial Characteristics
Picture Aspect Ratio: 16:9
Pixel Count Horizontal x Vertical: 7,680 x 4,320/3,840 x 2,160
Pixel Aspect Ratio: 1:1 (Square Pixels)
Pixel Addressing: Pixel ordering in each row is from left to right, and rows are ordered from top to bottom
Picture Temporal Characteristics
Frame Frequency in Hertz (Hz): 120, 60, 60/1.001, 50, 30, 30/1.001, 25, 24, 24/1.001
Scan Mode: Progressive
Chromaticity Coordinates (CIE, 1931)
Red Primary: X 0.708/Y 0.292
Green Primary: X 0.170/Y 0.797
Blue Primary: X 0.131/Y 0.046
Reference White (D65): X 0.3127/Y 0.329
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Bob is an audio enthusiast who has written about consumer electronics for various publications within Massachusetts before joining the staff of CE Pro in 2000. Bob is THX Level I certified, and he's also taken classes from the Imaging Science Foundation (ISF) and Home Acoustics Alliance (HAA). Bob also serves as the technology editor for CE Pro's sister publication Commercial Integrator. In addition, he's studied guitar and music theory at Sarrin Music Studios in Wakefield, Mass., and he also studies Kyokushin karate at 5 Dragons in Haverhill, Mass. Have a suggestion or a topic you want to read more about? Email Robert at email@example.com
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