Extra space not wanted at the end of a title page

Question

I did a title page using the titlepage environment and used \vfill between the entries (for instance name, title, date, etc.) so that they would be equally spaced and the whole title page would fill all of the page.

This implies that there should be an equal blank space at the top of the page (before my first entry) and at the bottom of the page (after my last entry). Nevertheless, it is not what I get. What can I do to fix it? I do not want to alter my geometry settings.

\documentclass[12pt]{article} 

\usepackage[letterpaper,textwidth=7in,textheight=9.5in]{geometry}

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt}
\fancyfoot[c]{--~\thepage~--}

\begin{document}
\newgeometry{textwidth=6.5in,textheight=9in}
\begin{titlepage} 
\begin{center}
\textbf{Name of the lab} \par
Blabla
\vfill
Title
\vfill
\normalsize\textbf{Name}
\vfill
Report presented to: \par
Someone
\vfill
\today
\end{center}
\end{titlepage}

\end{document}

Blank space before the first entry: Blank space after the last entry:

Answer 1

There are two factors that influence your problem. The default behavior of geometry is to divide the available vertical space for the top and bottom margins in a ratio 2:3. Another slight source for space is the usage of the center environment. Just use \centering that doesn't add vertical space.

You can look at how geometry sets the page elements by adding the showframe option.

\documentclass[12pt]{article} 

\usepackage{geometry}
\geometry{letterpaper,textwidth=7in,textheight=9.5in,showframe}

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt}
\fancyfoot[c]{--~\thepage~--}

\begin{document}
\newgeometry{textwidth=6.5in,textheight=9in,vmarginratio=1:1}

\begin{titlepage}
\centering
\textbf{Name of the lab} \par
Blabla
\vfill
Title
\vfill
\normalsize\textbf{Name}
\vfill
Report presented to: \par
Someone
\vfill
\today
\end{titlepage}

\restoregeometry

\section*{Introduction}
\vfill
\begin{center}
1
\end{center}

\end{document}