The definition of a screen is described by the number of pixels within the height of the image (not the TV). CRT televisions and most DVDs are what is known as standard definition (SD) in which we see 576 pixels. The arrival of high-definition (HD) in 2005 was seen via televisions that were standard HD Ready 720p (p for progressive) and Full HD 1080p. The HDTV 1080p began to appear on store shelves in 2008. This is where we are today, and is known as Full HD, but now Ultra HD (HD4K) has come into existence.
How is 4K-HD defined against SD, HD, HD-720p and HD-1080p?
This image definition has to be multiplied four times in order to work, thereby doubling the width and height. As previously mentioned, the definition of a screen comes from the height of the image and the number of pixels held within. So we double the height of the image, which is 1920 x 2, equalling 3840. And we double the pixel amount, which is 1080 x 2, equalling 2160. The height and the pixel number have each been doubled, hence where the 4 in 4K comes from.
We then need to put those two elements (numbers) back into a screen, so we multiply 3840 x 2160 to see a 4K pixel number, which is 8,294,400 pixels. This definition is called Ultra HD.
The "4K" is a format used by the technical staff so that they know what ratios to shoot and display Ultra HD in. For example, it is usually 4096 x 2160, but that may vary. For example, CinemaScope is displayed as 1.85:1.
What are the benefits of Ultra HD?
Clear as crystal images are the first benefit. They are actually supposed to be called UHD for ultra high definition, except that manufacturers have started to use the term 4K before they update to CEA standards. The CEA said that the 4K terminology, with a number plus a letter, seemed more like marketing services that UHD TV. That is why Sony Blu-ray have just recently started using the phrase "Mastered in 4K," which are movies made in 1080p, but were originally shot in 4K, which will be scaled to be distributed TV on UHD TVs when UHDs arrive.
Blu-Ray discs bought today can be viewed on UHD
Simply put, the Blu-ray scaling will be optimized with a higher encoding rate on the Blu-ray "Mastered in 4K" versus Blu-ray standard. In short, 4K may still coexist with the Ultra HD (at least on Blu-ray anyway).
Where does UHD beat the Full HD?
Besides the obvious interest for manufacturers to revitalize TV sales, there are benefits to the consumer. The most obvious is the improvement of the image quality, where the equivalent size in pixels visible goes from 1080p to 2160p, which will make each pixel undetectable to the naked eye.
The UHD screen now has the ability to increase and decrease the viewer's feeling of immersion, with a "cinema-like" feel. Bigger screen TVs are now inevitable, as UHD will allow most manufacturers to offer even greater diagonal length without deteriorating the image quality (TV screens are measured diagonally).
UHD may bring about a new 3D age
Ultra HD is theoretically going to facilitate the development of 3D technology without glasses, based on the recent development of "definition loss against gain of view." Currently we have to use glasses to see 3D. The glasses allow us to see two contrasting images, which trick the brain into thinking an image is 3D. Using UHD, they have created a technique where the contrast is created on the screen, by contrasting the slightly-defined against the ultra-defined. The idea is in its early stages, but 3D TV without glasses may become a reality soon enough.
UHD may be inevitable
Today most modern movies are shot in 4K, and even some TV shows are being shot in 4K. So the use of 4K TV and movies may one day be forced upon people in the same way that people were forced to watch digital TV instead of analogue.
The downsides to UHD will disappear with time
In time, Ultra HD will be celebrated and marketed more than 3D TV. But even now, there are a lot of similarities between 3D TV and UHD. There is a lack of content, technical problems to overcome, and excessive prices for TVs and accessories. For example, the first 4K projector available to the public has been made by Sony, who are charging $18,999 for it. These are problems that will fade away with time, as market forces do their magic and bring prices down, whilst pushing content up.
Are people waiting for 8K TV?
Even the most optimistic UHD sales staff do not predict a big upsurge in popularity for the UHD (4K) TV until the end of 2014 and early 2015. But the idea of 4K being replaced by 8K is not expected to be a problem, as the technology that will replace 4K with 8K is still in its infancy.
Even if the expected developments for the 4K were used for 8K, the 4K would still work better (HEVC codec, DVB-T2, etc). Ultra HD foreshadows much of what will be the TV of the future. In the meantime, your Full HD screens are still going to be the most popular TV format, since they are cheaper, have more content, and work for people who want a screen that has a diagonal that is below 55 inches.