> The 8th bit was used for selecting the color pallet (eventually; initially the 8th bit was just ignored)
The palette selection was achieved by...
(Yes, it's that cool)
Shifting the 7-pixel group half-pixel to the left (IIRC, could be to the right). It was a trick used in HP terminals (Woz worked for HP) and printers to have nicer fonts without doubling the pixel clock and character ROM sizes.
For color, this put the pixels at offset positions in relation to the chroma wheel and that caused the switch from green/purple to orange/blue.
The palette selection was achieved by...
(Yes, it's that cool)
Shifting the 7-pixel group half-pixel to the left (IIRC, could be to the right). It was a trick used in HP terminals (Woz worked for HP) and printers to have nicer fonts without doubling the pixel clock and character ROM sizes.
For color, this put the pixels at offset positions in relation to the chroma wheel and that caused the switch from green/purple to orange/blue.