Palette
Description
The Coupé’s palette is 128 colours of which 16 can be chosen (MODE1,2&4) or 4 in MODE3 - see Screen Modes.
The default colours are the same as the ZX Spectrum in pot positions 0-7, followed by the same colours again but changed to be equivalent to having the BRIGHT attribute being set.
MODE1 has a ZX Spectrum compatible FLASH feature, BRIGHT is supported via the upper 8 pot positions of the default palette but is transparent to the user when emulating Spectrum behaviour.
The palette can be altered on a per-line basis using the line interrupts in MODEs 2-4 to give multiple colours on screen or to produce effects in the border area on the Splash Screen or see the Fred 41 menu by Matt Round for a simple but effective example.
Complex real-time effects can be seen in more advanced demos such as The Lyra III, Mnemodemo II or in utilities such as BorderTron 3000.
Trivia
Originally the machine was envisaged to have 256 colours but limited to 64 colours on the development machine due to a shortage of pins on the ASIC that was to be used, see Hardware Bugs but had the extra intensity (BRIGHT) added on Simon Goodwin's suggestion in it's pre-ASIC design stage to give 128.
According to an interview with Bo Jangeborg intervention whilst writing Flash! also upped it to 128:
I convinced them to do away with the hardware flash in the high colour modes. That allowed for a significantly larger pallet. I think it went from 64 to 128 colours. That also allowed me to transfer some pictures from the Atari without too big a degradation.