Part 3 of 4
UltraHD (referred to as 4K) quadruples video resolution from about two million HDTV pixels to more than eight million pixels. That’s good. Pixel count is easy to explain, but difficult to see.
8K UltraHD doubles UltraHD (UHD) resolution, which quadruples the number of UHD pixels. Again, the pixel-count is easy to explain. Yet even more difficult to see.
HDTV 1080 lines x 1920 pixels/line = 2,073,600 pixels
UltraHD 2130 lines x 3840 pixels/line = 8,294,400 pixels
8K UltraHD 4320 lines x 7680 pixels/line = 33,177,600 pixels
As the early days of HDTV, 8K UHD video sources will be in short supply for some time. The current resolution benefit of 8K, with the assistance of AI-upscale software, is primarily focused on wall-sized screens.
The Viewable Difference
High Dynamic Range is more complicated to explain but easy to see. HDR expands the difference between the darkest black and brightest white pixel. It creates an expansive grayscale that produces more detailed side-by-side simultaneous dark-bright light. This extended broader grayscale also increases color gamut. This may be the most significant difference since the introduction of color.
UHD HDR Color
The C.I.E. is the international committee of color standards. Their C.I.E. color chart defines the visible range of color and sets video standards. UltraHD HDR employs two C.I.E. color standard options, DCI P3 and REC.2020.
Digital Cinema Initiative P-3 represents 45.5% of the C.I.E. color chart. REC.2020 equals 75.8% of the color chart. For reference, HDTV REC.709 equals 35.9% of the chart.
DCI P-3 satisfies current UHD standards. REC.2020 is the future objective. In either case, both support more lifelike natural colors that are considerably more visible than UHD pixels.
HDR utilizes competing formats. Your choice of video sources dictates the format. The TV must decode the format. Front running formats include HDR10, Dolby Vision, HDR10+, and HGL.
HDR10 is the baseline default format for all HDR sources and TVs.
Dolby Vision has become the high-performance option.
HDR10+ is an alternative to Dolby Vision.
HGL is the NextGenTV broadcast format.
HDR formats are dependent on HDMI specifications. Non-compliant interconnecting cable or AV components produce blank screens or downgrade the video to standard dynamic range.
– HDMI 2.0a supports HDR10.
– HDMI 2.0b adds support for HGL.
– HDMI 2.1 adds support for 10bit HDR10+ and 12bit Dolby Vision.
The UltraHD Premium Alliance, an association of manufacturers, studios, and others, established baseline UltraHD HDR specifications.
– 3840 x 2160 video resolution.
– LCD 0.05nit to 1000 nit brightness.
– OLED 0.0005nit to 540 nit brightness.
– 90% of the DCI P3 color gamut.
The UltraHD Premium logo validates product meets their standards.