> 4 million colours That would be 22 bit, which seems quite unlikely. Perhaps you're thinking of 4096 (= 2^12 = (16)^3)? It seems only 256 of them could be s

> 4 million colours That would be 22 bit, which seems quite unlikely. Perhaps you're thinking of 4096 (= 2^12 = (16)^3)? It seems only 256 of them could be shown at once and only 240 could be modified [1][2][3]? If those are correct then it is more limited than VGA, which could show 256 colours chosen from 262144 (= 2^18 = (64)^3). Some Archimedes resolutions were more like low-end SVGA though [1]. [1] https://lowendmac.com/2018/acorn-archimedes-computers/ https://lowendmac.com/2018/acorn-archimedes-computers/ [2] https://en.wikipedia.org/wiki/Color_depth https://en.wikipedia.org/wiki/Color_depth Edit: [3] Original brochures! http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP474_A4000.pdf http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochu... and http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP390_A5000.pdf http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochu...