[ylere]

HDR is less about the colors and more about achieving a wider range of brightness levels (hence increasing the total dynamic range). It's typically encoded using 10 or 12-bit color depth, and metadata is added to the media on how to map the colors' luminance/brightness values (e.g., what darkest and brightest values of a image/video should be). This is then used to transform HDR content into appropriate color and luminance values for your specific monitor (e.g., the reference monitor used for grading might have a peak brightness of 1000 nits, but yours might be different, or have a different luminance-response curve or support a different color space).