Network Working Group L. McIntyre
Request for Comments: 3950 Consultant
Obsoletes: 3250 G. Parsons
Category: Standards Track Nortel Networks
J. Rafferty
Brooktrout Technology
February 2005
Tag Image File Format Fax eXtended (TIFF-FX) - image/tiff-fx
MIME Sub-type Registration
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document describes the registration of the MIME sub-type
image/tiff-fx. The encodings are defined by File Format for Internet
Fax and its extensions.
1. Introduction
This document describes the registration of the MIME sub-type
image/tiff-fx. The encodings are defined by File Format for Internet
Fax [TIFF-FX] and its extensions.
This document is a product of the IETF Internet Fax Working Group.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119
[REQ].
2. TIFF-FX Definition
Tag Image File Format Fax eXtended (TIFF-FX), is defined in detail by
RFC 3949, "File Format for Internet Fax" [TIFF-FX].
McIntyre, et al. Standards Track [Page 1]RFC 3950 image/tiff-fx February 2005
While a brief scope and feature description is provided in this
section as background information, the reader is directed to the
original TIFF-FX specification (File Format for Internet Fax) to
obtain complete feature and technical details.
2.1. TIFF-FX Scope
This document defines a TIFF-based file format specification for
enabling standardized messaging-based fax over the Internet. It
specifies the TIFF fields and field values required for compatibility
with the existing ITU-T Recommendations for Group 3 black-and-white,
grayscale and color facsimile. TIFF has historically been used for
handling fax image files in applications such as store-and-forward
messaging. Implementations that support this file format
specification for import/export may elect to support it as a native
format. This document recommends a TIFF file structure that is
compatible with low-memory and page-level streaming implementations.
Unless otherwise noted, the current TIFF specification [TIFF] and
selected TIFF Technical Notes [TTN1, TTN2] are the primary references
for describing TIFF and defining TIFF fields. This document is the
primary reference for defining TIFF field values for fax
applications.
2.2. TIFF-FX Features
Some of the features of TIFF-FX are:
- TIFF-FX is capable of describing bilevel, grayscale, palette-
color, full-color and mixed content image data.
- TIFF-FX includes a number of compression schemes that allow
developers to choose the best space or time tradeoff for their
applications.
- TIFF-FX is designed to be extensible and to evolve gracefully as
new needs arise.
3. MIME Definition
This document defines the image/tiff-fx MIME sub-type to refer to
TIFF-FX Profiles J, C, L and M encoded image data and any future
TIFF-FX extensions, or a subset. The image/tiff-fx content type MAY
be used when black-and-white image data is encoded using TIFF-FX
Profiles S or F, or a subset, however, the image/tiff content type
SHOULD be used.
McIntyre, et al. Standards Track [Page 2]RFC 3950 image/tiff-fx February 2005
4. IANA Registration
To: ietf-types@iana.org
Subject: Registration of Standard MIME media type image/tiff-fx
MIME media type name: image
MIME subtype name: tiff-fx
Required parameters: none
Optional parameters: none
Encoding Considerations:
This media type consists of binary data. The base64 encoding
should be used on transports that cannot accommodate binary data
directly.
Security considerations:
TIFF-FX utilizes a structure which can store image data and
attributes of this image data. The fields defined in the TIFF-FX
specification are of a descriptive nature and provide information
that is useful to facilitate viewing and rendering of images by a
recipient. As such, the fields currently defined in the TIFF-FX
specification do not in themselves create additional security
risks, since the fields are not used to induce any particular
behavior by the recipient application.
TIFF-FX 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 TIFF-FX
specification. Indeed, the definition of fields which would
include such processing instructions is inconsistent with the
goals and spirit of the TIFF-FX specification.
The MIME type and file extension defined by this document MUST NOT
be used to blindly select a processing program. It is up to the
implementation to determine the application (if necessary) and
render the image to the user.
McIntyre, et al. Standards Track [Page 3]RFC 3950 image/tiff-fx February 2005
Interoperability considerations:
The ability of implementations to handle all the defined
applications (or profiles within applications) of TIFF-FX may not
be ubiquitous. As a result, implementations may decode and
attempt to display the encoded TIFF-FX image data only to
determine that the image cannot be rendered.
Published specification:
TIFF-FX (Tag Image File Format Fax eXtended) is defined in:
RFC 3949, "File Format for Internet Fax", February 2005, Buckley,
R., Venable, D., McIntyre, L., Parsons, G., and J. Rafferty.
Applications which use this media type:
Imaging, fax, messaging and multi-media
Additional information:
Magic number(s):
II (little-endian): 49 49 2A 00 hex
MM (big-endian): 4D 4D 00 2A hex
File extension(s): .TFX
Macintosh File Type Code(s): TFX
Person & email address to contact for further information:
Lloyd McIntyre
Lloyd_McIntyre@Dell.com
Glenn W. Parsons
gparsons@nortelnetworks.com
James Rafferty
jraff@brooktrout.com
Intended usage: COMMON
Change controller: Lloyd McIntyre
McIntyre, et al. Standards Track [Page 4]RFC 3950 image/tiff-fx February 2005
5. Security Considerations
TIFF-FX utilizes a structure which can store image data and
attributes of this image data. The fields defined in the TIFF-FX
specification are of a descriptive nature and provide information
that is useful to facilitate viewing and rendering of images by a
recipient. As such, the fields currently defined in the TIFF-FX
specification do not in themselves create additional security risks,
since the fields are not used to induce any particular behavior by
the recipient application.
TIFF-FX 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 TIFF-FX specification. Indeed, the
definition of fields which would include such processing instructions
is inconsistent with the goals and spirit of the TIFF-FX
specification.
The MIME type and file extension defined by this document MUST NOT be
used to blindly select a processing program. It is up to the
implementation to determine the application (if necessary) and render
the image to the user.
6. References
6.1. Normative References
[TIFF-FX] Buckley, R., Venable, D., McIntyre, L., Parsons, G., and J.
Rafferty, "File Format for Internet Fax", RFC 3949,
February 2005.
6.2. Informative References
[TIFF] Adobe Developers Association, TIFF (TM) Revision 6.0 -
Final, June 3, 1992.
[REQ] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[TTN1] Adobe PageMaker 6.0 TIFF Technical Notes, Sept. 14, 1995,
http://partners.adobe.com/asn/developer/pdfs/tn/TIFFPM6.pdf
[TTN2] Adobe Photoshop TIFF Technical Notes, Replacement TIFF/JPEG
specification, March 22, 2002,
http://partners.adobe.com/asn/developer/pdfs/tn/
TIFFphotoshop.pdf
McIntyre, et al. Standards Track [Page 5]RFC 3950 image/tiff-fx February 2005
Annex A. List of edits to RFC 3250
+----+---------+-------------------------------------------------+
| No.| Section | Edit |
+----+---------+-------------------------------------------------+
| 1. | All | Updated references from RFC 2301 to |
| | | draft-ietf-fax-tiff-fx-13.txt |
+----+---------+-------------------------------------------------+
| 2. | 5 | MIME Definition - added a "SHOULD" statement to |
| | | stress that image/tiff is the preferred content |
| | | type when representing Profiles S and/or F. |
+----+---------+-------------------------------------------------+
| 3. | 7 | Revise security considerations. |
+----+---------+-------------------------------------------------+
| 4. | 3 | Merged sections 2 & 3 and renumbered. |
+----+---------+-------------------------------------------------+
McIntyre, et al. Standards Track [Page 6]
RFC 3950 image/tiff-fx February 2005
Authors' Addresses
Lloyd McIntyre
10328 S. Stelling Road
Cupertino, CA 95014 USA
Phone: +1-408-725-1624
EMail: lloyd10328@pacbell.net or
Lloyd_McIntyre@Dell.com
Glenn W. Parsons
Nortel Networks
P.O. Box 3511, Station C
Ottawa, ON K1Y 4H7
Canada
Phone: +1-613-763-7582
Fax: +1-613-967-5060
EMail: gparsons@nortel.com
James Rafferty
Brooktrout Technology
410 First Avenue
Needham, MA 02494
USA
Phone: +1-781-433-9462
Fax: +1-781-433-9268
EMail: jraff@brooktrout.com
McIntyre, et al. Standards Track [Page 7]RFC 3950 image/tiff-fx February 2005
Full Copyright Statement
Copyright (C) The Internet Society (2005).
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
McIntyre, et al. Standards Track [Page 8]
