You tell PP3 where your own preamble is with the filename
parameter `latex_preamble' in the input script, for example:
filename latex_preamble mypreamble.tex
The file mypreamble.tex contains your LaTeX preamble macros
and must reside in the current directory, or in another directory where
TeX looks for its files.
The following is the contents of the file wiki.tex of the
PP3 distribution. It is the original user LaTeX preamble that
was used for the Wikipedia Project, see Successful use of PP3.
01 \usepackage{amsmath} 02 \usepackage[T1]{fontenc} 03 \IfFileExists{eulervm.sty}{\usepackage{eulervm}}{} 04 \usepackage{relsize} 05 \IfFileExists{t1pmy.fd}{ 06 \renewcommand*{\sfdefault}{pmy} 07 }{ 08 \renewcommand*{\sfdefault}{phv} 09 } 10 \renewcommand{\Messier}[1]{\footnotesize{\scriptsize M}\,#1} 11 \renewcommand{\NGC}[1]{\footnotesize{\scriptsize NGC}\,#1} 12 \renewcommand{\IC}[1]{\footnotesize{\scriptsize IC}\,#1} 13 \renewcommand{\FlexLabel}[1]{{\bfseries #1}} 14 \renewcommand{\TicMark}[1]{{\mdseries\scriptsize\mathversion{normal} #1}} 15 \AtBeginDocument{\sffamily\boldmath}
And this is what it does:
\IfFileExists thing tests whether the package is available on the
current computer. The package is included only if it exists.
\smaller which can be very useful in text
labels. It reduces the current font size. For example I can say
set_label_text LEO 32 "\\smaller Regulus"
\sffamily and
to bold Greek letters with \boldmath.