scale text size

Question

I'm stuck with a somewhat unusual problem. The poster template that I have to use outputs A4 pages, while the final poster will be A0. That means, I have to scale everything by a factor of 4 (linearly). I think this is done such that "normal" font sizes are readable on the A0 poster from a distance. The problem is that they are actually much too large and I want to shrink them. I do not seem to be able to set a small enough font. My preferred solution would be to scale a bigger font. That would normally not be desirable because it is better to use a font that was designed to be smaller, but remember that in this case the fonts will be scaled back when printing.

My current solution uses something along the lines of \fontsize{5mm}{6mm}\selectfont to set a custom font size. This only sets the font size of most of the text and not of the text for: math, siunitx package and the bibliography. If I set the font size using \small or similar, I do get the same fontsize everywhere. Is it possible to mimic one of these commands, but with a custom size?

Answer 1

I ended up using koma-scripts scrartcl documentclass. This class provides scaling for the fonts, although I'm not sure about the internals of this package. Currently I use \documentclass[fontsize=6pt]{scrartcl} to set the font size to 6pt, but any LaTeX length is accepted. Luckily my template was included as a package, not as a documentclass and as such I was able to use this method.