RFC2346 - Making Postscript and PDF International

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　　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 RFCrecommend 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", RFC2046,
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.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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