rgb(red, green, blue, names=NULL)
The values returned by rgb can be used with a
col= specification in graphics functions or in par.
rainbow, hsv, gray.
rgb(0,1,0)
u01 <- seq(0,1, length=11); all(rgb(u01,u01,u01) == gray(u01))
reds <- rgb((0:15)/15, g=0,b=0, names=paste("red",0:15,sep="."))
reds