TR: 4K and Ultra HD: same same…but different!

4K and Ultra HD are becoming popular buzzwords in the tech culture. But what exactly is do they mean?

From a technical standpoint, 4K is synonymous to a digital image with an horizontal pixel count somewhere between 4000 and 5000. 

In the cinema industry, 4K has become a popular option for capturing and stocking images. A typical native resolution amongs digital movie cameras is 4096 x 2160. According the lens or aspect ratio choice of the director of photography, many « 4K » resolutions are possible (for example, a movie shot in a 2.39 :1 aspect ratio will have an image resolution of 4096 x 1716).

In august 2012, the Consumer Electronic Association (CEA) introduced Ultra HD. Amongst the specifications guidelines of this next generation video standard,  image resolution starts at 3840 x 2160, 4 times the pixel density of 1920 x1080 HD.   Image resolution comparison chart. 

As seen in the image resolution comparison chart, Ultra HD and 4K do not share the same aspect ratio (1.78 :1 vs 1.90 :1).  Complying to the well established 1.78 :1 (16/9) standard probably explains why the CEA didn’t went for 4096×2160 for Ultra HD. Easy upscaling must have played a role also, as going from 1920×1080 to 3860 x 2160 requires a simple multiplication. 

So, in conclusion, while both 4K and Ultra HD  specificications portfolios have a lot in common, we are actually talking about two different standards emerging from competing industries.