better warning

diff --git a/evolis-printer.pl b/evolis-printer.pl
index a753b27..1a7a1f2 100755 (executable)
--- a/evolis-printer.pl
+++ b/evolis-printer.pl
@@ -42,7 +42,7 @@ while(<>) {
        } elsif ( $c eq 'Db' ) {
                my ( $color, $two, $data ) = @a;
                print "$c;$color;$two;... bitmap\n";
-               $two eq '2' or die '2';
+               $two eq '2' or die 'only 2 colors supported';
                my $path = "$name-Db-$color-$page.pbm"; $page++;
                save_pbm $path, 648, 1015, $data;       # FIXME 1016?
        } elsif ( $c eq 'Dbc' ) { # XXX not in cups