While this is visible on modern emulation and modern monitors, this would actually produce real solid extra colours on a CRT monitor.
To dither finely the 8 RGB colours cannot produce more than 27 colours because of redundancy in the result colour from diferent combinaison.
*Opposite colours from the 2x2 RGB cube would produce grey
Ex : Black + White = grey, Yellow + Blue = Grey.
*some other mix would produce already existing basic colours
Ex : RED + Blue = Magenta.
*would only remain :
= 6 intermediary colours : Lime, sky blue, Purple, Sea Green, Orange, Lavender.
= Darker Basic colours when mixed with Black : Dark blue, Dark Red, Dark Cyan...and so on.
= Lighter basic colours when mixed with White : Light red, Light Cyan... equivalent to Amstrad CPC's Pastel colours.
This leads to the 3-level RGB cube generated from the 1-bit RGB cube in high horizontal resolution and CRT monitor effect.
== Links ==