Hercules was a video card, not a terminal. The color for monochrome is defined by the monitor, of course. Green phosphor CRTs were quite common in the IBM PC world (starting with IBM's original 5151 monitor I think), but for terminals actually used on Unix machines other colors were more typical. The VT-100 series were blue, I believe; and later DEC terminals went with amber. White was reasonably common. I don't think I ever used a real terminal on a Unix box with a green phosphor.
My mistake, i was remembering old pc 8086 with hercules card and green monitor. Also that look resembled the ibm3151 green terminals, but i liked more the yellowish ones.
Hercules was a video card, not a terminal. The color for monochrome is defined by the monitor, of course. Green phosphor CRTs were quite common in the IBM PC world (starting with IBM's original 5151 monitor I think), but for terminals actually used on Unix machines other colors were more typical. The VT-100 series were blue, I believe; and later DEC terminals went with amber. White was reasonably common. I don't think I ever used a real terminal on a Unix box with a green phosphor.