RFC2346 - 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.

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

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.