7.13 Note on ERC escaped color sequences

The built-in IRC client erc has the ability to colorize any text using escape sequences that start with ‘^C’ (inserted with C-q C-c) and are followed by a number for the foreground and background.⁴ Possible numbers are 0-15, with the first entry being the foreground and the second the background, separated by a comma. Like this ‘^C1,6’. The minimum setup is this:

(add-to-list 'erc-modules 'irccontrols)
(setq erc-interpret-controls-p t
      erc-interpret-mirc-color t)

As this allows users the chance to make arbitrary combinations, it is impossible to guarantee a consistently high contrast ratio. All we can we do is provide guidance on the combinations that satisfy the accessibility standard of the themes:

Modus Operandi

Use foreground color 1 for all backgrounds from 2-15. Like so: C-q C-c1 where ‘N’ is the background.

Modus Vivendi

Use foreground color 0 for all backgrounds from 2-13. Use foreground ‘1’ for backgrounds 14, 15.

Colors 0 and 1 are white and black respectively. So combine them together, if you must.