How to change font size mid document?

Question

I want to create a TeX document for which the first (summary) page is \documentclass[10pt]{article}, but for which the rest of the document is \documentclass[12pt]{article}. Is there an easy way to do this?

Answer 1

The following will locally reconfigure everything as if a different size agrument had been given to the document class. I assume not every setting will be effective though. But at least all the sizing macros will be appropriately redefined.

\documentclass[12pt,a4paper]{book} 

\usepackage{lipsum}

\newenvironment{localsize}[1]
{%
  \clearpage
  \let\orignewcommand\newcommand
  \let\newcommand\renewcommand
  \makeatletter
  \input{bk#1.clo}%
  \makeatother
  \let\newcommand\orignewcommand
}
{%
  \clearpage
}

\begin{document}
\lipsum
\begin{localsize}{10}
  \lipsum
\end{localsize}
\end{document}

Note: This is based on loading the original size definitions of the book class named bk10.clo, bk11.clo, bk12.clo, so 10, 11, 12 are the possible arguments, corresponding to the options 10pt, 11pt, 12pt of the document class.

For using with another class (for instance article), the prefix bk used in

  \input{bk#1.clo}%

needs to be replaced by the one used by the respective class (for instance size). Some classes like memoir support a wider range of sizes.

Answer 2

You can change font size using \fontsize{10}{12}\selectfont (the first number is the pt size of the font, the second number the space in pts between lines: this becomes the value of \baselineskip), but in general I think it's better to try using things like \tiny, \small, \scriptsize, \normalsize, \footnotesize, \large, \Large, \LARGE, \huge and \Huge (and the corresponding environments (e.g., \begin{small} ... \end{small}). I think \footnotesize would give you a 10pt font in a document with 12pt set in its document class options.

And if the summary page is done using a special environment, like \begin{abstract} ... \end{abstract} likely what you want can be done a completely different way, such as by using the abstract package. (It's hard to give concrete advice without knowing more about the details of the summary page, however.)

Answer 3

A ConTeXt solution:

• If you want the footnotes, headers and footers, etc in the first page to correspond to 10pt and rest of the document to correspond to 12pt:

\setupbodyfont[10pt]
\starttext
Abstract
\page
\setupbodyfont[12pt]
....
\stoptext

• If you want all the footnotes, headers and footnotes, etc. to correspond to 12pt font size

\setupbodyfont[12pt]
\starttext
\start
\switchtobodyfont[10pt]
Abstract: ...
\stop
\page
Rest of the document
\stoptext

Answer 4

An easy way would be to create a 10pt document for the summary and include its pdf output within the 12pt document. You could use the pdfpages package for that purpose.

If you really wish to use just one document, you could redefine \normalsize and all the other size macros like \footnotesize, \scriptsize etc. you can find the definition inside the .clo files like size10.clo.

But I would choose the easier way, splitting the document code.