# Biblatex + kpfonts = unclean line breaks?

I am using biblatex and biber to create the bibliography of my thesis. I am also using kpfonts.

I noticed that in almost every entry of my bibliography there is one line in which a symbol or letter extends over the right border. Take a look:

This problem only occurs in the bibliography section of the document, all normal text paragraphs have proper edges. The problem also does not occur when I am not using kpfonts.

Therefore I am concluding that the problem lays in the interplay of biblatex with kpfonts. Probably biblatex is using a different font internally to determine the spacing?

Here are the relevant code lines:

\documentclass[a4paper,12pt]{book}
\usepackage[nomath]{kpfonts}
\usepackage[backend=biber,style=numeric,citestyle=numeric-comp,bibencoding=utf8,url=false]{biblatex}
...
\begin{document}
...
\setcounter{biburllcpenalty}{7000}
\setcounter{biburlucpenalty}{8000}
\printbibliography


Who has an idea how to solve this?

• my first try would be \usepackage{microtype}. May 18 '20 at 9:04
• I had not heard of microtype before, but it did the trick. All problems are solved. How do I mark this question as solved when there is only a comment? May 18 '20 at 9:09
• For more help on line breaks in the bibliography see tex.stackexchange.com/q/442308/35864. May 18 '20 at 15:39
• Not relevant to the question, but style=numeric,citestyle=numeric-comp, is equivalent to the shorter style=numeric-comp,. Usually bibencoding=utf8, is not needed, since the encoding can be inferred from the document (and you probably want to use UTF-8 for both the .tex and .bib file). You can (and should) remove \addcontentsline{toc}{chapter}{Bibliography} in favour of adding heading=bibintoc to the \printbibliography call: \printbibliography[heading=bibintoc]. Usually I would put the \setcounter lines in the preamble. May 18 '20 at 15:42

Try \usepackage{microtype}, it allows fonts to stretch a bit and so can often help in such cases.