Almost all fonts, nowadays, are provided with LaTeX control
(fd) files, so the temptation to risk the
problems of \newfont is usually easy to
resist.
However, one temptation remains, arising from the way that LaTeX restricts the sizes of fonts. In fact, the restriction only significantly applies to the default (Computer Modern) and the Cork-encoded (T1) EC fonts, but it is widely considered to be anomalous, nowadays. In recognition of this problem, there is a package fix-cm which will allow you to use the fonts, within LaTeX, at any size you choose. If you’re not using scaleable versions of the fonts, most modern distributions will just generate an appropriate bitmap for you.
So, suppose you want to produce a heading in Computer Modern Roman at 30 points, you might be tempted to write:
\newfont{\bigfont}{cmr10 at 30pt}
\begin{center}
\bigfont Huge text
\end{center}
which will indeed work, but will actually produce a worse result than
\usepackage{fix-cm}
...
\begin{center}
\fontsize{30}{36}\selectfont
Huge text
\end{center}
Note that the fix-cm package was not distributed until the
December 2003 edition of LaTeX; if you have an older distribution,
the packages type1cm (for CM fonts) and
type1ec (for EC fonts) are available.
Fix-cm doesn’t has one or two omissions — fonts the LaTeX team did not consider useful, or something; the CM dunhill fonts (as CM, but with stretched ascenders) and the CM fibonacci font (which is only available in 8-point design size) are certainly missing. If fix-cm doesn’t do the job, try the type1xx packages, or the anyfontsize package.
A further alternative might be to switch to the Latin Modern fonts (which provide a close simulacrum of the Computer Modern set); these fonts were scaleable from their first distribution, and don’t therefore need any such trick as the above.
This answer last edited: 2013-06-04
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=fontsize