# Should one always use exscale when using lmodern?

At the moment I only use summation signs with symbols which have a normal high and also no summation signs in subscripts. Due to this post is it correct that I should always use the exscale package when using the lmodern fonts? And is it correct that the package will load the CMEX10font for the summation signs?

• Much as it pains me to say you should do as egreg says, I think yes is probably the right answer (but the font is lmex10 not cmex10 if you are using lmodern) – David Carlisle Aug 27 '14 at 18:00
• The lmex10 and cmex10 fonts are quite the same, so using the latter will not be distinguishable; if you happen to use \sum in a section title you'll notice a big difference between using exscale or not. – egreg Aug 27 '14 at 19:18
• @DavidCarlisle I checked the fonts in Acrobat under the fonts listing and there it shows me CMEX10, maybe this is lmex10, but I don't find any hint about lmex10 in my document. – user2653422 Aug 28 '14 at 8:02

The problem is not only in using \sum in subscripts, as the following example shows. The version without exscale has a clearly wrong output.

## Without exscale

\documentclass{article}
\usepackage{lmodern}

\textheight=2cm % just for the example

\begin{document}
Some text\footnote{Because $\sum_{k=1}^{n}=n(n+1)/2$.}
\end{document}


## With exscale

\documentclass{article}
\usepackage{lmodern}
\usepackage{exscale}

\textheight=2cm % just for the example

\begin{document}
Some text\footnote{Because $\sum_{k=1}^{n}=n(n+1)/2$.}
\end{document}


• Thank you for pointing out it has wrong output. It is a bit strange that lmodern without an additional package is missing the function to scale the sum sign and that this issue wasn't already fixed. – user2653422 Aug 28 '14 at 7:59