%\cleardoubleevenemptypage

% ensure we are on a double page
\ifcase\numexpr \modulo{\value{page}}{2} \relax
% don't add any extra pages
\or
\hbox{}
\vspace{5mm}
\begin{center}
\tiny
--- This page is unintentionally left blank ---
\vfill
:P
\end{center}
\newpage
\fi

\addchap[Campusplan]{}
\thispagestyle{empty} %keine Seitenzahl
\AddToShipoutPicture*{\put(0,0){%
\parbox[b][\paperheight]{\paperwidth}{%
\vfill
\centering
\adjincludegraphics[height=\pageheight,keepaspectratio,trim={0 0 {.5\width} 0},clip]{img/campusplan_highlighted.pdf}%
\vfill
}}}
\mbox{}
\newpage
\thispagestyle{empty} %keine Seitenzahl
\AddToShipoutPicture*{\put(0,0){%
\parbox[b][\paperheight]{\paperwidth}{%
\vfill
\centering
\adjincludegraphics[height=\pageheight,keepaspectratio,trim={{.5\width} 0 0 0},clip]{img/campusplan_highlighted.pdf}%
\vfill
}}}
\mbox{}