font size in print output

[Thorsten Meyer]

I've been trying to control the font size in print output (with octave compiled
freshly from mercurial) like this:
octave:1> plot(1:10, 1:10);
octave:4> print bla2.eps -color
octave:5> print bla3.eps -color -F:20

The postscript plots look identical. But with
        diff -u bla2.eps bla3.eps
I see
        
[...]
 0.050 0.050 scale
 0 setgray
 newpath
-(Helvetica) findfont 140 scalefont setfont
+(Helvetica) findfont 200 scalefont setfont
 gsave % colour palette begin
 /maxcolors 64 def
 /HSV2RGB {  exch dup 0.0 eq {pop exch pop dup dup} % achromatic gray


so apparently some fontsize gets scaled. But the actual text in the plot seems
to get its size set explicitly. This makes sense to me because the text
fontsizes are defined in the graphics front end and can be set with
        set(gca, "fontsize", 20)
        xlabel("bla", "fontsize", 20)
and so on.
But what is the meaning of the -F:20 option in the print command?

Also:
when I plot first to eps and then to png like this:

        octave:1> plot(1:10, 1:10);
        octave:2> print bla1.eps
        octave:3> print bla1.png
The generated images have different font size (relative to the image size). And
both font sizes are much smaller than the font size in the original plot window.
Is that intended behaviour?

regards

thorsten