# Establish \fontseries for entire document

I want to use the light weight of the Open Sans package as my default font for a paper. It works perfectly fine using the following:

\begin{document}
{\fontseries{l}\selectfont
\input{...}
}
\end{document}


(of course there's more, but you get what I mean)

Although this works fine, I'm not really satisfied as this looks quite messy. I tried using renewcommand but could not figure out how to make \fontseries{l} \selectfont my default sans font.

Also, I'd like to do something similar for bold writing: I'd like to use \fontseries{sb} there. As I said before, this code (and thus the font weights) work like a charm when I use the mentioned commands within my document.

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semantically same question as in "How can one change an entire document to use bold font?" The first one should be generalized, rephrased and both should be merged. – Stefan K. Apr 14 '13 at 18:06

The default font can be set by changing \encodingdefault, \familydefault, \seriesdefault, and \shapedefault. In your example, I would go for
\renewcommand{\seriesdefault}{l}

works great! Just in case anybody is looking for this: \renewcommand{\bfseries}{\fontseries{sb}\selectfont} makes the bold font semi-bold for me. – Daniel Apr 6 '13 at 11:00