In fact, I found the answer myself: as soon as one variable is output that has multibyte characters in it, output switches to Unicode an all other (ISO-Latin1) characters are output as Unicode as well. To prevent this from happening, rather than writing print OUT $myunicodestring; print OUT $converter->convert("blöd"); which wouldn't have worked anyway, I now use $myisolatinstring = $converter->convert($myunicodestring); print OUT $myislatinstring etc. using Text::iconv now all works fine. Thanks, Björn