4K Projector and Video Technology
4K is an emerging standard for resolution in digital film and computer graphics. The name comes from its approximately 4,000 pixels of horizontal resolution. The fact that it describes the horizontal resolution is contrary to the standard resolutions 720p and 1080p, which represent the number of vertical pixels. 4K represents the horizontal resolution because there are numerous aspect ratios used in film — so while the horizontal resolution stays constant, the vertical resolution depends on the video source (a.k.a. letterboxing). There are several different resolutions that qualify as 4K.
Quad Full High Definition (QFHD), at 3840 x 2160 pixels, doubles the 1080p high-definition television standard in both the vertical and horizontal dimensions. However, it has often been debated if this resolution should be classified as 4K since it is fewer than 4000 pixels horizontally.
In July 2010, YouTube began streaming certain videos at 4096 × 2304 pixels (in the 16:9 aspect ratio) to 4096 x 3072 (4:3). Registered users at YouTube are allowed to upload videos with a resolution higher than 1080p.
In digital film, the pixel resolution varies by aspect ratio. Examples of 4K digital recording devices are the Dalsa Origin (announced in 2003 and released in 2006 as the first commercially available 4K digital cinema camera), the Red One (announced in 2006 and released in 2007), the Red Epic (released in early 2011), and the Sony CineAlta F65 (announced in April 2011). The Dalsa Origin system records images at a resolution of 4096 × 2048 and the Red One records images at 4096 × 2304.
|Full Aperture 4K||4096 × 3112||1.32:1||12,746,752|
|Academy 4K||3656 × 2664||1.37:1||9,739,584|
|Digital cinema 4K||4096 × 1714||2.39:1||7,020,544|
|Digital cinema 4K||3996 × 2160||1.85:1||8,631,360|
|Full Aperture 4K||4096 × 3112||4:3||1:1||12,746,752|
|Academy 4K||3656 × 2664||1.37:1||1:1||9,739,584|