What Is 4K Resolution? Overview and Perspective of Ultra HD

4K refers to one of two high definition resolutions: 3840 x 2160 pixels or 4096 x 2160 pixels. 4K is four times the pixel resolution, or twice the line resolution (2160p), of 1080p (1920 x 1080 pixels).

The other high definition resolutions in use are 720p and 1080i. These are the resolutions most frequently used in larger screen televisions to create better-detailed pictures.

• 4K resolution is used in commercial digital cinema using the 4096 x 2160 option, where many films are shot or finalized in 4K by upscaling from 2K (1998 x 1080 for the 1.85:1 aspect ratio or 2048 x 858 for 2.35:1 aspect ratio).
• Under its two official consumer labels, Ultra HD and UHD, 4K is well established in the consumer and home theater landscape, using the 3840 x 2160 pixel option (technically that is 3.8K, but saying 4K is easier).
• In addition to Ultra HD or UHD, 4K is also referred to in professional settings as 4K x 2K, Ultra High Definition, 4K Ultra High Definition, Quad High Definition, Quad Resolution, Quad Full High Definition, QFHD, UD, or 2160p.

Why 4K?

What makes 4K resolution significant is that with the use of ever-larger TV screen sizes as well as video projectors, it provides much more detailed and less pixel visible images than 1080p. 1080p looks great up to about 65-inches, and can still look good in larger screen sizes, but 4K can deliver an even better-looking image as screen sizes continue to increase.

How 4K Is Implemented

• There are plenty of 4K Ultra HD TVs available, as well as a growing number of 4K and 4K-enhanced video projectors.

• For added support in home theater setups, most AV home theater receivers have either 4K pass-through and/or 4K video upscaling capability.
• 4K content is available from several streaming sources, such as Netflix, Fandango at Home, and Amazon, as well as via the Ultra HD Blu-ray Disc format and players.

• On the satellite part of the equation, DirecTV and Dish are able to deliver a limited selection of pre-recorded and live 4K content via satellite to its subscribers (provided they have both a compatible satellite box, compatible TV, and subscribe to the appropriate plan).
• For those that prefer accessing content via cable, your choices are definitely limited. So far, Comcast provides a limited amount of 4K live and on-demand programming, plus access to 4K Netflix. If you have a 4K Ultra HD TV, check with your local cable provider to see if they offer any compatible 4K service.
• Over-the-air TV broadcasting is where 4K implementation is lagging. Although South Korea and Japan have taken the lead with regular 4K TV broadcasts, it is finishing field-testing in the U.S. to iron out issues such as compatibility with the current broadcast system and added infrastructure costs that stations will incur. The U.S. 4K TV broadcast system is referred to as ATSC 3.0 (NextGen). Select stations in the 40 largest U.S. TV markets are expected to start regular broadcasting by the end of 2020.

What 4K Really Means for Consumers

The increasing availability of 4K delivers consumers a greatly improved video display image for larger screen applications, and can greatly reduce the ability for viewers to see any visible pixel structure on the screen unless you place yourself extremely close. This means even smoother edges and depth. When combined with faster screen refresh rates, 4K has the potential to deliver almost as much depth as 3D—without the need for glasses.

The implementation of Ultra HD doesn't make a 720p or 1080p TV obsolete, although, as 4K Ultra HD TV sales pick-up and prices come down, fewer 720p and 1080p TVs are being made. Also, the current HDTV TV broadcast infrastructure will not be abandoned anytime soon, even as ATSC 3.0 begins to be used for content transmission.

Of course, just as with the 2009 DTV transition, there may come a date and time certain where 4K may become the default TV broadcast standard, but that means a lot of infrastructure needs to be in place.

Beyond 4K and Ultra HD

What lies beyond 4K? How about 8K? 8K is 16 times the resolution of 1080p. There are a limited number of 8K TVs available for purchase by U.S. consumers, with Samsung taking the lead, but there is no real 8K content available to watch in the U.S. This means that for some time viewers will be viewing images on 8K TVs that are upscaled from 4K, 1080p, 720p, or other lower resolution. However, Japan has started broadcasting one channel of 8K content.

Video Resolution vs. Megapixels

Here's how to compare 1080p, 4K and 8K resolution to the pixel resolution of even modestly priced digital still cameras:

• 1080p (1920x1080) is 2.1 megapixels.
• 4K (3840 x 2160 or 4096 x 2160) is about 8.5 megapixels.
• Only with 8K (7680 x 4320 pixels – 4320p) do you get into the pixel resolution range of the best professional digital still cameras – 33.2 megapixels. You are most likely taking photos with much higher resolution than you can see on your TV screen when it comes to video content.

Color, Contrast, and More

Of course, all the above being said, you are the one that needs to be satisfied with what you are seeing on your TV screen—increased resolution is one part, but other factors such as video processing/upscaling, color consistency, black level response, contrast, screen size, and how the TV physically looks in your room all need to be taken into consideration.

Frequently Asked Questions

• What does 4K mean? Technically, 4K refers to the fact that the screen has a horizontal display resolution of approximately 4,000 (4K) pixels. The "K" stands for "kilo," which denotes "one thousand." The two high-definition resolutions are 3840 x 2160 pixels or 4096 x 2160 pixels.
• How do you clean a 4K TV screen? The steps to clean a flat screen TV are the same, no matter the resolution: turn the television off, and then wipe it gently with a dry, soft cloth. For stubborn stains, dampen the cloth with equal parts distilled water and white vinegar, or with a cleaner made specifically for flat screens.
• What is 4K upscaling? 4K upscaling, or video upscaling, is the act of matching the pixel count of an incoming video signal to the pixel count of the TV. A processor analyzes the video resolution and creates additional pixels to match the number of pixels on the 4K TV screen.