[tex-live] texlive paper sizes

Reinhard Kotucha reinhard.kotucha at web.de
Sun Apr 7 04:00:05 CEST 2013

On 2013-04-06 at 23:43:27 +0200, Patrick Gundlach wrote:

 > Am 06.04.2013 um 23:23 schrieb Reinhard Kotucha <reinhard.kotucha at web.de>:
 > > On 2013-04-06 at 22:45:54 +0200, Patrick Gundlach wrote:
 > > 
 > >> Hi,
 > >> 
 > >> the paper sizes in install-tl-20130406 look a bit incorrect to me:
 > >> 
 > >> For example, in tlpaper.pm:
 > >> 
 > >>  "a5"       => "14.85x21.0cm",
 > >> 
 > >> the A, B and the C series are always rounded to the nearest mm.
 > >> 
 > >> Don't know if this has any influence though.
 > > 
 > > There is no need round values in mm or cm, PostScript use bp anyway
 > > and the error should be less than ±5bp.  Since 1mm < 5bp, it's ok.
 > I don't understand how this makes sense with my comment above. If I
 > tell the application the wrong size (148.5mm instead of 148mm) -
 > how would PostScript be able to determine the correct size (148mm)?

PostScript doesn't use these values at all, it simply passes them to
the output file, and only if they are specified at all.  PdfTeX uses
them in order to create the MediaBox entry, but in both cases they
have no influence on anything else.  Maybe the LaTeX geometry package
uses them in order to calculate page layout parameters if the
papersize isn't specified explicitly.
 > But again, I don't know if these sizes are actually used somewhere,
 > so It might not be worth discussing that issue at all.

They are used by printers in order to select the correct paper tray.
It's ok if the error is less than ±5bp.

Given that values are rounded, the size of an A4 page is 210m×297mm.
If you cut it into two A5 pages, the width of each A5 page is exactly
148.5mm, the value used by TeX Live.  What matters here are the values
in bp.

Whenever I specify a papersize, I use values in bp as listed
somewhere in an ancient (1996) Ghostscript distribution:


In TeX Live you can specify a default papersize but IMO it's better to
specify it explicitly in each document.  The default papersize of TL
is just a fallback.  It's never a good idea to rely on fallbacks.

Anyway, what TeX Live does is correct, as far as I can see.
Everything is fine if rounding errors are less than 5bp (1.74mm).


Reinhard Kotucha                                      Phone: +49-511-3373112
Marschnerstr. 25
D-30167 Hannover                              mailto:reinhard.kotucha at web.de
Microsoft isn't the answer. Microsoft is the question, and the answer is NO.

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