I thought of this question while using some old terminals to access an electronic file system at my local library (yep, I’m an intellectual). Why are old monochrome displays green? I know, some of them were the greyscale, like older TV sets, but only one of the 4-5 terminals has a greyscale screen. The rest are as green as Chicago on St. Paddy’s Day. Why are the screens greenscale (Is that a word? I don’t think so.) instead of greyscale?
Two things come to mind right away, there may be other reasons.
-
A phosphor coating that produced bright white light would burn out faster. Phosphor burn can be seen on old airport monitors & old video games. I have the arcade version of Gauntlet, and you can clearly see where the white fields normally display when the machine it turned off. Colored fields, especially green & blue, are hardly noticeable.
-
Green is a less harsh & more pleasing color for the eye. Less of an irritant than white or red. Designers were thinking of user comfort & health, even 10+ years ago.
The old green-screens (amber was also popular, but not as common as green) were that way because at their low refresh rates, it is much eaiser on the eyes to look at green-on-black than black-on-white or white-on-black.
freido:
A good place to see amber monochromes is at an airport. Look for the screens displaying the status of varying craft by flight number. At most of the airports I’ve been to (at least in the US), that info has been displayed on an amber screen. Thought you’d like to know.