[Tex/LaTex] Scrbook: Using fallback calculation to setup font sizes

biblatexfontsfontsizekoma-scriptwarnings

When using the class scrbook and customizing the font size prior the usage of \printbibliography I got these warning (and in big documents I got them several times):

Class scrbook Warning: Using fallback calculation to setup font sizes
(scrbook) for basic size `12pt' on input line 32.

MWE:

\documentclass{scrbook}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[backend = biber]{biblatex}
\renewcommand*{\bibfont}{\normalfont\changefontsizes{12pt}}

\usepackage{filecontents}    
\begin{filecontents}{\jobname.bib}
@online{GLS:datasheet,
    title = "GLS Datasheet",
    organization = "Optoelectronics Research Centre",
    howpublished = "Website",
    date = "2004-09",
    urldate = "2013-07-01",
    url = "http://www.southampton.XXXX",
    address = "Southampton, United Kingdom"
}
\end{filecontents}

\addbibresource{\jobname.bib}

\begin{document}
\KOMAoptions{fontsize=12pt}
\nocite{*}
\printbibliography
\end{document}

Do I have to expect unexpected results?
And it that is the case, what can I do against it? Otherwise how could I possibly silent these warnings?

Best Answer

This message tells you that KOMA-Script has a problem with your given fontsize (see the answer of @cgnieder for the mechanism KOMA-Script uses).

Why do you not only use \documentclass[fontsize=12pt]{scrbook}? Then you can delete \KOMAoptions{fontsize=12pt} and \renewcommand*{\bibfont}{\normalfont\changefontsizes{12pt}}.

The low level commands to change the fontsize are for example 

\fontsize{12pt}{14.5pt}\selectfont

or (depending on your font and standard fontsize!) you can use \large for 12 pt fontsize if you have a 11 pt standard font.

You can enclose titlepage, table of contence and bibliography with for example 

{\fontsize{12pt}{14.5pt}\selectfont ...}

to change the standard font size only for the part ... .

But that is only a hack. I would oversee this astonishing rule and use 11 pt everywhere ...

Related Question