Making Postscript and PDF International

Network Working Group                                          J. Palme
Request for Comments: 2346                     Stockholm University/KTH
Category: Informational                                        May 1998


                Making Postscript and PDF International

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   Certain text formats, for example Postscript (MIME-Type:
   application/postscript; file extension .ps) and Portable Document
   Format (MIME-Type: application/pdf; file extension .pdf) specify
   exactly the page layout of the printed document. The commonly used
   paper format is different in North America and the rest of the world.
   North America uses the 'Letter' format, while the rest of the world
   mostly uses the ISO-standard 'A4' format. This means that documents
   formatted on one continent may not be easily printable on another
   continent. This memo gives advice on how to produce documents which
   are equally well printable with the Letter and the A4 formats. By
   using the advice in this document, you can put up a document on the
   Internet, which recipients can print without problem both in and
   outside North America.

   A very short summary of the advice in this document: If you are using
   U.S. Letter paper format, ensure that both the left and right margins
   are at least 21 mm (0.8 in). If you are using A4 paper format, ensure
   that both the top and bottom margins are at least 33 mm (1.3 in).

Table of Contents

   1. Introduction                                                  2
   2. Two methods for printing on different paper formats           2
      2.1 Method 1: Use wider margins                               2
      2.2 Method 2: Print with reduced size                         3
      2.3 Method 3: Buy paper in the A4 size                        4
   3. Acknowledgements                                              4
   4. Security Considerations                                       4
   5. References                                                    4
   6. Author's Address                                              5
   7. Full Copyright Statement                                      6

1.    Introduction

   Certain text formats, for example Postscript (MIME-Type:
   application/postscript; file extension .ps) and Portable Document
   Format (MIME-Type: application/pdf;  file extension .pdf) specify
   exactly the page layout of the printed document. The commonly used
   paper format is different in North America and the rest of the world.
   North America uses the 'Letter' format, while the rest of the world
   uses the 'A4' format.

   The North American Letter format is 216 x 279 mm (8.5 x 11 in) while
   the ISO standardised A4 format is 210 x 297 mm (8.3 x 11.7 in). The
   Letter format is thus 6 mm (0.2 inches) wider, while the A4 format is
   18 mm (0.7 inches) taller.

   This means that documents formatted on one continent may not be
   printable on another continent. It is oboviously desirable that
   documents on the Internet are printable on all continents. This paper
   gives advice on how to achieve this.

   This memo is not intended for HTML documents, but the advice may be
   of value also for HTML developers in case they are using fixed-size
   graphics and fixed WIDTH sizes of objects in HTML documents.

2.    Three methods for printing on different paper formats

2.1   Method 1: Use wider margins

Paper format
you use when
converting
the document                                 Suggested minimal margins
to Postscript Paper
or PDF        orien-      Suggested change   Left   Right  Top    Bottom
              tation      of margins
------------  -----------  -----------------  -----  -----  -----  -----
A4           Portrait     Add 18 mm (0.7     20 mm  20 mm  33 mm  33 mm
             (upright,    inches) to the top 0.8"   0.8"   1.3"   1.3"
             vertical)    of page and bottom
                          of page margins

A4           Landscape    Add 18 mm (0.7     33 mm  33 mm  15 mm  15 mm
             (lying,      inches) to the     1.3"   1.3"   0.6"   0.6"
             horizontal)  left and right
                          margins

Letter       Portrait     Add 6 mm (0.2      20 mm  26 mm  15 mm  15 mm
             (upright,    inches) to the     0.8"   1.0"   0.6"   0.6"
             vertical)    right margins

Letter       Landscape    Add 6 mm (0.2      15 mm  15 mm  21 mm  21 mm
             (lying,      inches) to the top 0.6"   0.6"   0.8"   0.8"
             horizontal)  of page and bottom
                          of page margins

   The reason why you have to add 18 respectively 6 mm to both the top
   and the bottom margin is that you do not know what kind of printer
   the recipient uses, and different printers feed paper in different
   ways, requiring the margin to be added either at the top or the
   bottom of the paper. Left and right margins on any paper format
   should be at least 20 mm wide to accomodate filing with ISO 838 hole
   punches.

   Note: Ensure that also headers, footers, and page numbers are within
   the suggested minimal margins. Many word processors put headers,
   footers and page numbers outside the specified text margins.

2.2   Method 2: Print with reduced size

   This is a method useful for the recipient of a document with the
   wrong paper size: The recipient sets the printer to print with
   reduced size.  When the sender produces the PDF or Postscript files,
   the sender should 'print' with 100 % size, but when the recipient
   prints the PDF or Postscript files, and if the program for printing
   PDF or Postscript files allows this, the recipient should print the
   document with 94% or less of full size. Many programs for printing
   Postscript files do not allow this. In that case, the recipient can
   convert a Postscript document to PDF format and then print it with
   the PDF printing program.  This requires, however, that the recipient
   has the Adobe Acrobat Distiller program, which is not freeware.
   Recent versions of the freeware ghostscript can also convert to PDF
   format. The user may also have to specify the paper size as the
   actual paper size loaded in the printer, not the paper size specified
   when the document was converted to PDF or Postscript format.

   It is also possible to edit the Postscript file, and add a scale
   command to it, before sending it to the printer.

   Method 2 can be more difficult for the recipient, who has to manage
   these settings himself. However, manufacturers of printing software
   may in the future make method 2 easier by making this service
   automatic, perhaps controlled by a 'shrink to fit paper size'
   checkbox in the printing window and a 'default shrink to fit paper
   size' preference setting.

   In general, the authors of this RFC recommend PDF as the prefered
   formatted document distribution format over Postscript, not only
   because PDF printing programs typically feature a 'shrink to fit'
   option to handle different paper sizes elegantly, but also because
   PDF has built-in per page data compression, PDF files can be
   displayed without being fully downloaded, PDF is more portable, PDF
   has a better method of rendering fonts not available in the printer
   and PDF allows to embed URLs.

2.3   Method 3: Buy paper in the A4 size

   People in North America who often need to print international
   documents might choose to buy paper in the A4 size. It is available
   in the U.S. from many large paper distribution companies, and almost
   all laser printers support it.

3.    Acknowledgements

   Markus Kuhn has provided many helpful suggestions on this document.

   Adobe, Acrobat, Distiller, Exchange and Postscript are trademarks of
   Adobe Systems Incorporated or its subsidiaries.

4.    Security Considerations

   Adherence to the recommendations in this memo will increase the
   likelihood that a document will be readable, and look the same, to
   all recipients, and thus reduce the risk of misunderstanding. The
   recommendation does not in itself introduce any known new security
   risks. Of course, there might be a risk that reliance on the
   recommendations in this memo will make certain writers too sure that
   their documents will look the same.

   Postscript (TM) has well known security risks. These are discussed in
   [MIME].

5.    References

   A4     Writing paper and certain classes of printed matter
          - Trimmed sizes - A and B series, International
          Standard ISO 216, International Organization for
          Standardization, Geneva, 1975.

   ANSI   Bond Papers and Index Bristols - Common Sheet Sizes,
          North American National Standard ANSI X3.151, North
          American National Standards Institute, 1987.

   ISO    Paper - Holes for general filing purposes -
   838    Specifications, International Standard ISO 838,
          International Organization for Standardization,
          Geneva, 1974.

   Kuhn   Markus Kuhn: International Standard Paper Sizes.
          <URL:http://www.ft.uni-erlangen.de/~mskuhn/iso-
          paper.html>.

   PDF    Tim Bienz, Richard Cohn, James R. Mechan: Portable
          Document Format Reference Manual, Version 1.2, Adobe
          Systems Incorporated,
          <URL:http://www.adobe.com/supportservice/devrelation
          s/PDFS/TN/PDFSPEC.PDF>.

   MIME   Freed, N., and N. Borenstein, "Multipurpose Internet Mail
          Extensions (MIME) Part Two: Media Types", RFC 2046,
          November 1996.

6.  Author's Address

   Jacob Palme
   Stockholm University and KTH
   Electrum 230
   S-164 40 Kista, Sweden

   Phone: +46-8-16 16 67
   Fax:   +46-8-783 08 29
   EMail: jpalme@dsv.su.se

7.  Full Copyright Statement

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

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