# How to enable ligatures

I just notice that ligatures are not working on my system. For example:

\documentclass{article}
\renewcommand{\rmdefault}{ptm}
\begin{document}
data-flow missing ligature.
\end{document}


The "flow" word does not use the f-l ligature, appearing ugly.

This also happens with the default article font (if I removed the renewcommand):

I am setting with pdflatex.

Do I have to include a particular package?

• There are ligatures. Compare with f\/low, or try the fi ligature. – Ulrike Fischer Jun 1 '15 at 12:22
• Try f\/low to explicitely prevent a ligature. – Johannes_B Jun 1 '15 at 12:22
• Ok, I see the difference. So the problem then is just that in these fonts, the f-l ligature is extremely ugly? For me it looks just as if the kerning is smaller and the two characters are moved together to overlap. The f-i ligature looks correct, though. – Emit Taste Jun 1 '15 at 12:24

sorry to say, this is the fl ligature.
here is the output of running tex testfont on ptmr7t (the roman instance of the ptm fonts):