My current code is this:

In reply to Negative font help:

My current code is this:

feature calt {

sub @bright @apos' by @aneg;
sub @bneg o' @apos by o_both;
sub @bneg o' @pos by o_left;
sub @bneg o' by o_left;
sub @bneg [a c d e g q]' @pos by [a_both c_both d_both e_both g_both q_both];
sub @neg [a c d e q]' @pos by [a_right c_right d_right e_right q_right];
sub @bneg a' by a_left;
sub @bneg c' by c;
sub @bneg d' by d;
sub @bneg g' by g;
sub @bneg q' by q;
sub @pos @pos' by @neg;
sub @bpos @apos' by @aneg;
sub @posall @pos' by @neg;