The Amstrad CPC (old) palette features 27 colours, despite the fact that the Video system ([[Gate Array]] and [[CRTC]]) could actually handle 32 colours.
Because this This is a 3-level RGB custom palette. It is Cubic, generated by "Trigits" (ternary digits)
This palette is used by the [[CPC|Amstrad CPC]] old series only and is not found in any other computers (but clones of course).
[[File:Palette CPC gradiants.png]]
[[File:Cubic palette1.png]]