# Italic in section headings with Linux Biolinum

When compiling this minimal document

\documentclass[a4paper]{scrartcl}

\usepackage{fontspec}
\setromanfont[]{Linux Libertine O}
\setsansfont[]{Linux Biolinum O}

\begin{document}
\section{Test \emph{emphasized} Text}
abcd ldbflsdbgf
\section{Test \textit{italic} Text}
\end{document}


with xetex (you must have installed Linux Libertine and Linux Biolinum on your System) I get the following:

The emphasized/italic text is obviously not as bold as the rest of the section. Why does this happen and how can it be changed?

If I ask on my system

otfinfo -i /usr/local/texlive/2018/texmf-dist/fonts/opentype/public/libertine/LinBiolinum_RBO.otf


Family:              Linux Biolinum O
Subfamily:           Bold
Full name:           Linux Biolinum O Bold Oblique
PostScript name:     LinBiolinumOBO
Version:             Version 1.3.2
Unique ID:           FontForge 2.0 : Linux Biolinum O Bold Oblique : 30-10-2012
Designer:            Philipp H. Poll
Designer URL:        http://www.linuxlibertine.org
Manufacturer:        Philipp H. Poll
Vendor URL:          http://www.linuxlibertine.org
Copyright:           Linux Libertine by Philipp H. Poll,
Open Font under Terms of following Free Software Licenses:
Created with FontForge (http://fontforge.sf.net)
Sept 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,2012
Vendor ID:           PfEd


which means that the font doesn't correctly advertise its subfamily, which should be Bold Italic.

Solution:

\documentclass[a4paper]{scrartcl}

\usepackage{fontspec}

\setmainfont{Linux Libertine O}
\setsansfont{Linux Biolinum O}[
BoldItalicFont=* Bold Oblique
]

\begin{document}
\section{Test \emph{emphasized} Text}
abcd ldbflsdbgf

\textbf{\textit{\textsf{Italic}}}

\section{Test \textit{italic} Text}
\end{document}


For manually specifying the fonts:

\documentclass[a4paper]{scrartcl}

\usepackage{fontspec}

\setmainfont{Linux Libertine O}
\setsansfont{LinBiolinum}[
Extension=.otf,
UprightFont=*_R,
ItalicFont=*_RI,
BoldFont=*_RB,
BoldItalicFont=*_RBO,
]

\begin{document}
\section{Test \emph{emphasized} Text}
abcd ldbflsdbgf

\textbf{\textit{\textsf{Italic}}}

\section{Test \textit{italic} Text}
\end{document}

• Thank you very much! This seems to explain the issue but unfortunately this workaround fires me a "fontspec error: "font-not-found" The font "Linux Biolinum O Bold Oblique" cannot be found." so I seem to be needing to include the OTF files manually – chr May 21 '18 at 21:15
• @chr It should work if you add the font to your system fonts. Otherwise, yes, you have to add the font files manually. – egreg May 21 '18 at 21:16
• By the way, Libertinus Sans doesn't have a bold italic version. – egreg May 21 '18 at 21:17
• the Libertine fonts are added to my system fonts but seemingly this stuff is different under Windows – chr May 21 '18 at 21:21
• @chr I added how to load the fonts manually. I guess that the first way depends on the OS (and I'm not on Windows). – egreg May 21 '18 at 21:21

This depends on the fonts available. I also seem to lack Biolinum in a bold oblique shape as a system font, as it is not included in the SourceForge distribution. You could substitute something similar, as below (I grabbing Tex Gyre Heros, but perhaps something better is available):

    \setmainfont[]{Linux Libertine O} %\setmainfont, rather than \setromanfont

\setsansfont[
ItalicFont = LinBiolinumOI,
BoldFont = LinBiolinumOB,
BoldItalicFont = TeXGyreHeros-BoldItalic,
BoldItalicFeatures = {Scale =0.85},
]{Linux Biolinum O}


Looks like egreg (as usual) has a better solution!