Well, in theory, any colors from a 24Bits palette. The deal is not so much what colors it can produce, it is really about how many you will be able to display at the same time.
For example, in Text Mode, you can have 16 Colors for Foreground and 16 Colors for Background, this is the maximum number of combination you will be able to achieve. But, in each instances, you can actually pick and choose which 16 colors out of RGB 24bits palette.
In graphic mode, it is the same principle. Each pixel is 8Bits, so for example, in the Bitmap mode, you can display simultaneously 256 Colors from that Palette, always out of 24Bit values. There will be 8 Different palette that will be used from Bitmap, Tile Layers and/or Sprites. So, in theory, the maximum different colors you could display at the same time in graphic mode would be 2048 Colors.
However, if you play with raster interrupts, there would be ways to interchange the Palette values mid-screen, or change the palette altogether for the same layer, thus increasing the number of possible colors.
The whole concept of the computer is based off using 1 Byte per pixel.
@Luke,
Well, in theory, any colors from a 24Bits palette. The deal is not so much what colors it can produce, it is really about how many you will be able to display at the same time.
For example, in Text Mode, you can have 16 Colors for Foreground and 16 Colors for Background, this is the maximum number of combination you will be able to achieve. But, in each instances, you can actually pick and choose which 16 colors out of RGB 24bits palette.
In graphic mode, it is the same principle. Each pixel is 8Bits, so for example, in the Bitmap mode, you can display simultaneously 256 Colors from that Palette, always out of 24Bit values. There will be 8 Different palette that will be used from Bitmap, Tile Layers and/or Sprites. So, in theory, the maximum different colors you could display at the same time in graphic mode would be 2048 Colors.
However, if you play with raster interrupts, there would be ways to interchange the Palette values mid-screen, or change the palette altogether for the same layer, thus increasing the number of possible colors.
The whole concept of the computer is based off using 1 Byte per pixel.
So, I hope it answers the questions.
Cheers
Stefany