From Setting the Default Print Preview Zoom Factor :
The short answer is that it isn't
possible. Why? Because the hard-wired
starting point for Print Preview is to
use a "Whole Page" zoom factor. This
is because Print Preview is designed
to let you see what the page will look
like when printed, not necessarily to
read what is on that page. There is no
way to change this default zoom factor
setting in Print Preview itself.
There are workarounds, however. The
"Whole Page" zoom factor can vary in
size, depending on the size of the
actual page you are displaying and
depending on the size of the program
window you are using to display Word.
Thus, if you maximize the program
window, you end up with more space in
which to display the page in Print
The other possible workaround is to
create a macro that will display Print
Preview for you. The macro could be
assigned to a shortcut key or a
toolbar button (the Quick Access
toolbar in Word 2007) for easy use.
Here's an example of a macro that will
invoke Print Preview and then set the
zoom factor to 50%.
.Type = wdPrintPreview
.Zoom.Percentage = 50