4K resolution identifies a horizontal display resolution of around 4,000 pixels. Digital television set and digital cinematography commonly use a number of different 4K resolutions. In television set and consumer media, 3840 × 2160 (4K UHD) may be the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160 (DCI 4K).
The 4K television set market share increased as prices fell drastically during 2014 and 2015. By 2020, over fifty percent of U.S. households are anticipated to have 4K-capable TVs, a considerably faster adoption rate than that of Full HD (1080p).
K standards and terminology
The word “4K” is generic and identifies any resolution with a horizontal pixel count of around 4,000.5 A number of different 4K resolutions have already been standardized by various organizations.
DCI Digital Cinema System Specification
Comparison of DCI and UHD resolutions
In 2005, Digital Cinema Initiatives (DCI), a prominent standards organization in the cinema industry, published the Digital Cinema System Specification. This specification establishes standardized 2K and 4K container formats for digital cinema production, with resolutions of 2048 × 1080 and 4096 × 2160 respectively.6 The resolution of the video content inside follows the SMPTE 428-1 standard,6 which establishes the next resolutions for a 4K distribution:7
4096 × 2160 (full frame, 256∶135 or ≈1.90∶1 aspect ratio)
3996 × 2160 (flat crop, 1.85∶1 aspect ratio)
4096 × 1716 (CinemaScope crop, ≈2.39∶1 aspect ratio)
2K distributions can have a frame rate of either 24 or 48 FPS, while 4K distributions will need to have a frame rate of 24 FPS.6 Some articles declare that the conditions “2K” and “4K” were coined by DCI and refer exclusively to the 2K and 4K formats defined in the DCI standard. However, consumption of these conditions in the cinema industry predates the publication of the DCI standard, and they’re generally understood as everyday conditions for just about any resolution approximately 2000 or 4000 pixels wide, instead of names for specific resolutions.513