The Apple IIGS composite video output, a standard 'RCA' connector used for
composite NTSC compatible monitors, does not always display in color.
Because of effects known as color fringing (showing bits of color on the
edges of white characters), the color burst signal is turned off when the
computer is in text mode, making colored text, background, and borders
appear as black, white, or shades of grey. Turning off the color burst
eliminates color fringing and improves the legibility of text displayed
on composite color monitors. However, it makes testing of the color modes
of the Apple IIGS on a composite monitor impossible from a text-only program
such as the Control Panel or the Apple IIGS Diagnostics.
Color burst is enabled whenever any of the graphics modes (lo-res, hi-res,
or super hi-res) is switched on. Don't confuse the hi-res or super hi-res
mode with the text mode: when characters are drawn on the graphics screen
(as in the Apple IIGS Program Launcher, or when ProDOS 16 displays the 'One
moment please...' message while starting up), users may get the impression
that they are seeing text with a colored screen border, when in fact they're
not.