What is 4K? What is Ultra HD?

It’s simple, 4K means a clearer picture. It's more pixels (8,294,400 pixels) on the screen at once that creates images that are crisper and capable of showing more details than standard HD. Ultra High Definition is actually a derivation of the 4K digital cinema standard. However while your local multiplex shows images in native 4096 x 2160 4K resolution, the new Ultra HD consumer format has a slightly lower resolution of 3840 X 2160 which is what you get on the 16:9 ratio TVs you actually take home. This is one reason why some brands prefer not to use the 4K label at all, sticking with Ultra HD or UHD instead. What is the resolution of 4K? 4K resolution is 3840 x 2160 or 2160p.  A full HD 1080p image is only a 1920x1080 resolution.  4K screens have about 8 million pixels, which is around four times what your current 1080p set can display. A full HD 1080p image is 1080 rows high and 1920 columns wide.  A 4K image approximately doubles the numbers in both directions, making it approximately four times as many pixels total.   4K, also called 4K resolution, refers to a horizontal screen display resolution in the order of 4,000 pixels.  There are several different 4K resolutions in the fields of digital television and digital cinematography.  In television and consumer media, 4K UHD or UHD-1 is the dominant 4K standard. In the movie projection industry, Digital Cinema Initiatives (DCI 4K) is the dominant 4K standard. There are three main 4K resolution standards: UHD-1, or ultra-high-definition television (UHDTV), is the 4K standard for television and computer monitors. Resolution of 3840 × 2160 (16:9, or approximately a 1.78:1 aspect ratio);  UHD-1 is used in consumer television and other media, e.g. video games. UW4K is the ultra-wide 4K standard, with a resolution of 3840 × 1600, and an aspect ratio of 12:5 (2.4:1, or 21.6:9) This resolution is most commonly used on Ultra HD Blu-ray discs, and PC gaming monitors. DCI 4K which has a resolution of 4096 × 2160 pixels (256:135, approximately a 1.9:1 aspect ratio). This standard is only used in the film and video production industry.  The DCI 4K standard has twice the horizontal and twice the vertical resolution of DCI 2K. *Source from Wikipedia. Why is it called 4K? Because the images are around 4,000 pixels wide.  Yes, the industry named 1080 resolution after image height, but named 4K after image width.  To make it more confusing, you also might hear this resolution referred to as 2160p.  Like it’s not confusing enough?  They just make it more confusing.  Why do we need so many pixels? More pixels means more information. More information means sharper pictures. Sharper pictures are more engaging. More engaging content is more interesting.  We just get more picky with what we see nowadays. I'll see a huge difference? Maybe not as much of a thrill as you did when you upgraded your old CRT to a flatscreen, but 4K screens are noticeably sharper than 1080p screens.  Going from a 480 to a 1080p set, you’ll feel the difference;  display size is more powerful than any resolution jump could ever hope to be. Most people got big jumps in both screen size and resolution.  But this time screen sizes are staying about the same, with the most popular models falling in the 40 inch to 70 inch range. Most importantly, you'll only be able to see the resolution difference on a 4K set if you're watching 4K content and you're sitting close enough. What is this 8K? It's the next resolution standard up from 4K. Basically it doubles the pixel height and width again to yield approximately 32 million pixels.  An 8K display would also be UHD. 8K UHD, or 8K resolution, is the current highest ultra high definition television (UHDTV) resolution in digital television and digital cinematography.  8K refers to the horizontal resolution of 7,680 pixels, forming the total image dimensions of (7680×4320), otherwise known as 4320p. *source www.techradar.com updated 2018/04/01