[r] How to increase font size in a plot in R?

I came across this when I wanted to make the axis labels smaller, but leave everything else the same size. The command that worked for me, was to put:

par(cex.axis=0.5)

Before the plot command. Just remember to put:

par(cex.axis=1.0)

After the plot to make sure that the fonts go back to the default size.