RFC 3073

Portable Font Resource (PFR) - application/font-tdpfr MIME Sub-type Registration

📅 published March 2001, from ietf

RFC 3073: Portable Font Resource (PFR) - application/font-tdpfr MIME Sub-type Registration ✨

okay bestie, this one is all about the header info first 🎀 RFC 3073 is by J. Collins from Bitstream Inc. It's marked Category: Informational 📚 and dated March 2001. The header doesn't list anything it obsoletes or updates, so it stands on its own 💜

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 🌈

Abstract 🦋

This document describes the registration of the Multipurpose Internet Mail Extensions (MIME) sub-type application/font-tdpfr. The encoding is defined by the PFR Specification.

A Portable Font Resource (PFR) contains a set of glyph shapes. Each glyph shape is associated with a character code. The PFR format is designed to be both compact and platform-independent. It's intended to help fonts render accurately everywhere, whether or not the required fonts are already installed. It's giving "works everywhere" energy 💖

1. Conventions used in this document ✨

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [REQ]. These are the official requirement words, so they're the ones to watch 👀

2. Overview 🧚

This document describes the registration of the MIME sub-type application/font-tdpfr. The encoding is defined by [PFR].

3. PFR Definition 💅

PFR (Portable Font Resource) is defined by Bitstream Inc. in [PFR]. The documentation can be obtained from Bitstream at:

Bitstream Inc.
215 First Street
Cambridge MA 02142 U.S.A.
Phone: +1 617 497 6222
Fax:   +1 617 868 0784

A copy of this specification can also be found at:

http://www.bitstream.com/pfrspec/index.html

There's a brief scope and feature rundown here as background, but if you want the full feature and technical details, go to the original PFR specification [PFR] 📖

3.1 PFR Scope 🍓

A PFR contains a set of glyph shapes. Each glyph shape is associated with a character code. The PFR format is designed to be both compact and platform-independent. It's intended to help fonts render accurately in environments whether or not they have the required fonts already installed.

The glyph shape definitions in a PFR are resolution-independent. That means glyph definitions can be displayed or printed on devices with a wide variety of resolutions. Glyphs can also be rendered at any size, which is so iconic 🔥

3.2 PFR Features ⭐

Some of the features of the PFR format are:

Compact representation of glyph shapes
Independent of byte order and operating system
Independent of output device resolution
Fully scalable to any glyph size
Optional inclusion of bitmap glyph images
Adopted as the font standard by DAVIC, DVB, and DTG

4. Comments 💌

This document is submitted by J. Collins, Bitstream Inc. All comments should be directed to <jcollins@bitstream.com>.

5. MIME Definition 🎀

The PFR media type has been previously registered with IANA as application/vnd.truedoc. Because it has since been widely adopted as a standard font format by several standards bodies that have relationships with the Internet community, Bitstream was asked to re-register this media type within the IETF tree. Major glow-up 🦋

6. IANA Registration 📝

Here's the registration template, copied exactly:

To: ietf-types@iana.org
Subject: Registration of Standard MIME Media type
    application/font-tdpfr

MIME media type name: application

MIME subtype name: font-tdpfr

Required parameters: none

Optional parameters: none

Encoding considerations: Binary or base 64 required

Security considerations:

   PFR uses a structure that can store glyph image data and encoding
   arrays.  The fields defined in the PFR specification are of a
   descriptive nature and provide information that is useful to
   facilitate viewing and rendering of glyph images by a recipient.
   As such, the fields currently defined in the PFR specification do
   not in themselves create additional security risks, since the
   fields are not used to induce any particular behavior by the
   recipient application.

   PFR has an extensible structure, so that it is theoretically
   possible that fields could be defined in the future which could be
   used to induce particular actions on the part of the recipient,
   thus presenting additional security risks, but this type of
   capability is not supported in the referenced PFR specification.
   Indeed, the definition of fields that would include such
   processing instructions is inconsistent with the goals and spirit
   of the PFR specification.

Interoperability considerations: none

Published specification:

   The specification for this content type is available on request
   from:

   Bitstream Inc.
   215 First Street
   Cambridge MA 02142 U.S.A.
   Phone: +1 617 497 6222
   Fax:   +1 617 868 0784

A copy of this specification can also be found at:

   http://www.bitstream.com/pfrspec/index.html

Applications which use this media type:

   Netscape Communicator, Bitstream WebFont Maker, Hexmac Typograph

Additional information: None

Magic number(s): 50 46 52 30 hex

File extension(s): PFR

Macintosh File Type Code(s): Creator: 'b$pw' Type: 'PFR '

Person to contact for further information:

   "John Collins" <jcollins@bitstream.com>

Intended usage: common

Author/Change controller:

   "John Collins" <jcollins@bitstream.com>

⚠️ Security babe moment: the security section above is serious business. The fields in PFR are descriptive and don't trigger actions in the recipient today. The bit to really watch is that PFR is extensible, so future fields could be defined to make a recipient do things, which would add real security risk. The referenced spec doesn't support that, and adding such processing instructions would clash with the whole goal of the spec 🙅‍♀️

7. References 📚

[REQ]   Bradner, S., "Key words for use in RFCs to Indicate
        Requirement Levels", BCP 14, RFC 2119, March 1997.

[MIME1] Freed, N. and N. Borenstein,  "Multipurpose Internet Mail
        Extensions (MIME) Part One: Format of Internet Message
        Bodies", RFC 2045, November 1996.

[MIME4] Freed, N. and N. Borenstein,  "Multipurpose Internet Mail
        Extensions (MIME) Part Four: Registration Procedures", RFC
        2048, November 1996.

[PFR]   Bitstream Inc. "PFR Specification",
        http://www.bitstream.com/pfrspec/index.html

8. Author's Address 💜

John Collins
Bitstream Inc.
215 First Street
Cambridge, MA 02142

Phone: +1 617 520 8401
Fax:   +1 617 868 0784
EMail: jcollins@bitstream.com

9. 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.

Acknowledgement 🫶

Funding for the RFC Editor function is currently provided by the Internet Society. ✨

📦 where this page comes from

ietf: rfc3073 2001-03
💖 girlified by claude-haiku-5-5 on 2026-10-16: a language model's rewrite of the original, under its terms