A display system that provides 4,096 shades of color for each red, green and blue subpixel for a total of 68 billion colors.  For example, Dolby Vision supports 12-bit color.  A 36-bit color depth also means 12-bit color because the 36 refers to each pixel, not the subpixel.  See 
color depth, 
Dolby Vision and 
bit specifications.