[COFF] White Backgrounds on GUIs after Dark Backgrounds on Terminals?
Paul Winalski
paul.winalski at gmail.com
Sat Jun 17 02:08:21 AEST 2023
On 6/15/23, segaloco via COFF <coff at tuhs.org> wrote:
>
> So terminals, they started as typewriters with extra steps, a white piece of
> paper on a reel being stamped with dark ink to provide feedback from the
> machine. When video terminals hit the market, the display was a black screen
> with white, orange, green, or whatever other color of phosphor they bothered
> to smear on the surface of the tube. Presumably this display style was
> chosen as on a CRT, you're only lighting phosphor where there is actually an
> image, unlike the LCD screens of today. So there was a complete contrast
> shift from dark letters on white paper to light letters on an otherwise
> unlit pane of glass.
The phosphors on CRT screens don't last forever. You only want to
light them when necessary. CRTs also suffer from the problem of
burn-in. If you keep the same picture illuminated for a long period
of time that pixel pattern gets burned into the phosphors. This is
why the later GUI CRTs had screen saver software that displayed an
ever-changing picture to prevent burn-in. This isn't a problem with
the modern, non-cathode-ray displays. Good ol' flying toasters.
-Paul W.
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