I think the answer given above is wrong.
The file
http://www.ghostscript.com/doc/9.15/Use.htm#Change_default_size
sais:
"You can change the installed default paper size on an installed version
of Ghostscript, by editing the initialization file
gs_init.ps. This file
is usually in the Resource/Init directory somewhere in the search path.
See the section on finding files for details.
Find the line
% /DEFAULTPAPERSIZE (a4) def
Then to make A4 the default paper size, uncomment the line to change
this to
/DEFAULTPAPERSIZE (a4) def
For a4 you can substitute any paper size Ghostscript knows.
This supecedes the previous method of uncommenting the line % (a4) ....
Sometimes the initialization files are compiled into Ghostscript and
cannot be changed.
+------------------------------------------------------------------+
| On Windows and some Linux builds, the default paper size will be |
| selected to be a4 or letter depending on the locale." |
+------------------------------------------------------------------+
Regards
--
Wilfried Hennings
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