Ignoring page numbers in backup slides

Question

I am using the beamer document class in latex to make a presentation. I will have a number of back up slides which are there for offline viewing, reference etc. Beamer has a f

Answer 1

Another possibility - which was recently added to beamer - is to use the appendixframenumber template:

\documentclass[t]{beamer}

\setbeamertemplate{footline}{
  \hfill%
  \usebeamercolor[fg]{page number in head/foot}%
  \usebeamerfont{page number in head/foot}%
  \setbeamertemplate{page number in head/foot}[appendixframenumber]%
  \usebeamertemplate*{page number in head/foot}\kern1em\vskip2pt%
}

\begin{document}

    \begin{frame}
        slide in the main part
        \only<2>{blub}
    \end{frame}

    \appendix
    \section*{Backup}

    \begin{frame}
        \frametitle{backup}
        not counting in the total frame number
    \end{frame}

\end{document}