# Caption and reference of a figure in the introduction chapter

I have an introduction chapter defined with the command:

\chapter*{Introduction}


The captions of the figures within this chapter, that doesn't have a number like the others, are named:

"Figure 1", "Figure 2", etc.

then when I reference a figure with \ref{labelname} I see a number like 1,2 etc.

I don't like this way to reference a figure, because isn't like the other chapters. The captions of the first chapter for example are:

"Figure 1.1", "Figure 1.2" etc.

I'd like that the captions of the figures in the introduction to be:

"Figure I.1", "Figure I.2" etc.

then when I reference a figure with \ref{labelname} I see a number like I.1, I.2 etc. How can I do that?

Here an example code:

\documentclass[a4paper]{book}

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{lipsum}

\begin{document}
\chapter*{Introduction}
\lipsum[1]
\begin{figure}[h!]
\vspace{2cm}
\label{fig:intro}
\caption{Figure in the introduction}
\end{figure}

Look at the Fig.~\ref{fig:intro}.
I want it referenced as Fig.~I.1.

\chapter{A sample chapter}
\lipsum[1]

\begin{figure}[h!]
\vspace{2cm}
\label{fig:chap1}
\caption{Figure in chapter 1}
\end{figure}

Look at the Fig.~\ref{fig:chap1}.

\chapter*{Conclusion}
\lipsum[1]
\begin{figure}[h!]
\vspace{2cm}
\caption{Figure in the conclusion}
\label{fig:conc}
\end{figure}

Look at the Fig.~\ref{fig:conc}.
I want it referenced as Fig.~C.1.

\end{document}

-
Please provide a small MWE so that we don't have to construct a document for you. Easier for us to play around. – LaRiFaRi Mar 9 '14 at 10:30

This is a very simple solution. Notice! I moved the label below the caption statement.

\documentclass[a4paper]{book}

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{lipsum}

\begin{document}
\chapter*{Introduction}
\renewcommand{\thefigure}{I.\arabic{figure}}
\lipsum[1]
\begin{figure}[h!]
\vspace{2cm}
\caption{Figure in the introduction}
\label{fig:intro}
\end{figure}

Look at the Fig.~\ref{fig:intro}.
I want it referenced as Fig.~I.1.

\chapter{A sample chapter}
\renewcommand{\thefigure}{\arabic{chapter}.\arabic{figure}}
\lipsum[1]

\begin{figure}[h!]
\vspace{2cm}
\caption{Figure in chapter 1}
\label{fig:chap1}
\end{figure}

Look at the Fig.~\ref{fig:chap1}.

\end{document}

-
Thank you! It works well! But I have another problem... if I write a conclusion chapter like the introduction, the the figure within the conclusion are referenced starting from the last figure number in the last chapter. – nunzio13n Mar 9 '14 at 13:45
What's your goal? – Oliver Mar 9 '14 at 13:49
I have edited the question, but I have solved it by adding the line \setcounter{figure}{0} before the commend \renewcommand in the conclusion. – nunzio13n Mar 9 '14 at 13:54