Black rgba(0,0,0,0.8). Red rgba(255,0,0,0.8).
Green rgba(0,255,0,0.8). Blue rgba(0,0,255,0.8).

Black rgba(0%,0%,0%,0.4). Red rgba(100%,0%,0%,0.4).
Green rgba(0%,100%,0%,0.4). Blue rgba(0%,0%,100%,0.4).