A:Answer I believe it is RGB. The LG-provided product specifications mention "Color Gamut (Typ.) sRGB 99% (CIE1931)." If I'm interpretation this correctly, this means it uses RGB. See https://www.lg.com/us/monitors/lg-27uk670-b-4k-uhd-led-monitor.
But, please -- if I'm wrong, let me know. [I fix a great crow pie!]