The original 8 pen colors are simple but the high/low intensity bit isn't supported by the Amiga Console.device since it was an add-on to the standard for the PC. I don't have Termite so I don't know if it uses a custom terminal but if it does, the other 8 colors of the 16 color palette may work.
https://en.wikipedia.org/wiki/ANSI_escape_code has a table of some common RGB values used in various terminal packages. If you're on an ECS or OCS Amiga, you'll have to divide the red green and blue components by 16 and leave off any fractional parts.
