Why would LaTeX ignore the font size in the documentclass

Question

I have a LaTeX file. I'm experimenting with trying to reduce the font size (this is related to my other question here http://stackoverflow.com/questions/2636647/latex-changing-the-font-size-for-a-document-but-in-the-preamble-not-the-docum ).

The LaTeX file is generated from another programme. I have edited it to start with

\documentclass[4pt,a4paper,english]{report}

i.e. I am trying to make the text really small. However it doesn't work. I change that 4pt to anything and the font size is the same.

When running pdflatex on it, I get this message printed out.

LaTeX Warning: Unused global option(s):
    [4pt].

That might explain why the error message is

What could be going on here? How do I make it use the font size in the documentclass definition?

Answer 1

You can use only

10pt|11pt|12pt

in the default documentclass

I think you have to redefine the main text command to support smaller (unreadable) font sizes

Answer 2

There is no option 4pt defined for documentclass article, as it was already mentioned. So your 4pt is simply not recognized by LaTeX.

You can however use extsizes package, which allows some more size options: 8 through 12, 14, 17 and 20pt. However no support for 4pt. There exist other packages that allow for non-standard default sizes, listed at the same page.

Answer 3

Use \documentclass[10pt,a4paper,english]{article} and then specify \tiny after \begin{document}.