Network Working Group G. Parsons Request for Comments: 3302 Nortel Networks Obsoletes: 2302 J. Rafferty Category: Standards Track Brooktrout Technology September 2002 Tag Image File Format (TIFF) - image/tiff
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. Plea 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 (2002). All Rights Rerved. Abstract
This document describes the registration of the MIME sub-type
image/tiff. This document refines an earlier sub-type registration
in RFC 1528.
This document obsoletes RFC 2302.
1. Conventions ud in this document
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 RFC 2119 [REQ].
2. Overview
This document describes the registration of the MIME sub-type
image/tiff. The baline encoding of TIFF (Tag Image File Format) is defined by [TIFF].
3. Internet Fax Working Group
This document is a product of the IETF Internet Fax Working Group.
All comments on this document should be forwarded to the email
distribution list at <ietf-fax@imc>.
Parsons & Rafferty Standards Track [Page 1]
4. TIFF Definition
TIFF (Tag Image File Format) Revision 6.0 is defined in detail by
Adobe in [TIFF]. The documentation can be obtained from Adobe at:
Adobe Developers Association
Adobe Systems Incorporated
345 Park Avenue
San Jo, CA 95110-2704
Phone: +1-408-536-6000
Fax: +1-408-537-6000
A copy of this specification can also be found in:
/asn/developer/PDFS/TN/TIFF6.pdf
While a brief scope and feature description is provided in this
ction as background information, the reader is directed to the
original TIFF specification [TIFF] to obtain complete feature and
technical details.
4.1 TIFF Scope
TIFF describes image data that typically comes from scanners, frame
grabbers, and paint- and photo-retouching programs. TIFF is not a
printer language or page description language. The purpo of TIFF
is to describe and store raster image data. A primary goal of TIFF
is to provide a rich environment within which applications can
exchange image data. This richness is required to take advantage of the varying capabilities of scanners and other imaging devices.
不能前往吊唁短信Though TIFF is a rich format, it can easily be ud for simple
scanners and applications as well becau the number of required
fields is small.
4.2 TIFF Features
Some of the features of TIFF (from [TIFF]) are:
- TIFF is capable of describing bilevel, grayscale, palette-
color, and full-color image data in veral color spaces.
- TIFF includes a number of compression schemes that allow
developers to choo the best space or time tradeoff for their applications.
- TIFF is designed to be extensible and to evolve gracefully as
new needs ari.
Parsons & Rafferty Standards Track [Page 2]
- TIFF allows the inclusion of an unlimited amount of private or special-purpo information.
5. MIME Definition
5.1 image/tiff
The image/tiff content-type was previously defined in RFC 1528 as
containing TIFF 6.0 encoded image data, with specific reference made to a subt known as TIFF Class F. This document redefines the
original image/tiff definition to refer to TIFF 6.0 [TIFF] encoded
image data, consistent with existing practice for TIFF aware Internet applications. This definition is further enhanced by introducing the new "application parameter" (ction 6.2) to enable identification of a specific subt of TIFF and TIFF extensions for the encoded image
好句摘抄大全初中data.
5.2 Application parameter
There are cas where it may be uful to identify the application
applicable to the content of an image/tiff body. Typically, this
would be ud to assist the recipient in dispatching a suitable
rendering package to handle the display or processing of the image
file. As a result, an optional "application" parameter is defined
for image/tiff to identify a particular application’s subt of TIFF and TIFF extensions for the encoded image data, if it is known. No
values are defined in this document.
Example:
Content-type: image/tiff; application=foo
There is no default value for application, as the abnce of the
application parameter indicates that the encoded TIFF image is
Baline TIFF or that it is not necessary to identify the
application. It is up to the recipient’s implementation to determine the application (if necessary) and render the image to the ur.
黑猫白袜子
New values for the image/tiff application parameter must be approved by the IESG prior to registration. As a result, the publication of a description of parameter values in an RFC is required.
Guidelines on writing IANA considerations for RFCs can be found in
RFC 2434.
An application parameter is a hint to the receiver. It MUST NOT be
ud as a blind request to execute some arbitrary program.
Parsons & Rafferty Standards Track [Page 3]
Instead, it should be viewed rather as an indication of what sort of application would be able to handle the content most appropriately. 6. IANA Registration
To: ietf-types@iana丁香网五月
如何释怀一段感情Subject: Registration of Standard MIME media type image/tiff
MIME media type name: image
MIME subtype name: tiff
Required parameters: none
Optional parameters: application
There is no format specified for the value of this parameter
in addition to that specified by [MIME1]. Various
applications of TIFF may define values as required as hints
to the receiver. There is no default value for application,
as the abnce of the application parameter indicates that
the encoded TIFF image is Baline TIFF or that it is not
necessary to identify the application. It is up to the
implementation to determine the application (if necessary)
and render the image to the ur.
Encoding considerations:
This media type consists of binary data. The ba64 encoding
should be ud on transports that cannot accommodate binary
data directly.
Security considerations:
TIFF utilizes a structure which can store image data and
attributes of this image data. The fields defined in the TIFF specification are of a descriptive nature and provide
information that is uful to facilitate the viewing and
rendering of images by a recipient. As such, the fields
currently defined in the TIFF specification do not in
themlves create additional curity risks, since the fields
are not ud to induce any particular behavior by the
recipient application.
TIFF has an extensible structure, so that it is theoretically
possible that fields could be defined in the future which
could be ud to induce particular actions on the part of the
recipient, thus prenting additional curity risks, but Parsons & Rafferty Standards Track [Page 4]
this type of capability is not supported in the referenced
TIFF specification. Indeed, the definition of fields which
would include such processing instructions is inconsistent
with the goals and spirit of the TIFF specification as
defined to date.
Interoperability considerations:
The ability of implementations to handle all the defined
applications (or profiles within applications) of TIFF may
not be ubiquitous. As a result, implementations may decode
and attempt to display the encoded TIFF image data only to
determine that the image cannot be rendered. The prence of
the application parameter may aid in allowing this
determination before dispatching for rendering. However, it
should be noted that the parameter value is not intended to
convey levels of capabilities for a particular application.
Published specification:
TIFF (Tag Image File Format) is defined in:
TIFF (TM) Revision 6.0 - Final June 3, 1992
Adobe Developers Association
Adobe Systems Incorporated
345 Park Avenue
San Jo, CA 95110-2704
Phone: +1-408-536-6000
Fax: +1-408-537-6000
A copy of this specification can be found in:
/asn/developer/pdfs/tn/TIFF6.pdf
Applications which u this media type:
Imaging, fax, messaging and multi-media
Additional information:
Magic number(s):伺蛇
II (little-endian): 49 49 2A 00 hex
MM (big-endian): 4D 4D 00 2A hex
File extension(s): .TIF
Macintosh File Type Code(s): TIFF
Parsons & Rafferty Standards Track [Page 5]
Person & email address to contact for further information:
Glenn W. Parsons二年级上册数学期中测试卷
James Rafferty
Intended usage: COMMON
Change controller: James Rafferty
6. Security Considerations
TIFF utilizes a structure which can store image data and attributes
of this image data. The fields defined in the TIFF specification are of a descriptive nature and provide information that is uful to
facilitate the viewing and rendering of images by a recipient. As
such, the fields currently defined in the TIFF specification do not
in themlves create additional curity risks, since the fields are not ud to induce any particular behavior by the recipient计划免疫工作计划
application.
TIFF has an extensible structure, so that it is theoretically
possible that fields could be defined in the future which could be
ud to induce particular actions on the part of the recipient, thus prenting additional curity risks, but this type of capability is not supported in the referenced TIFF specification. Indeed, the
definition of fields which would include such processing instructions is inconsistent with the goals and spirit of the TIFF specification
as defined to date.
7. Changes from RFC 2302
* Correction of magic number
* Improvements of the curity considerations
* Change of change controller
* Various editorials to improve clarity
8. References
8.1 Normative References
[REQ] Bradner, S., "Key words for u in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Parsons & Rafferty Standards Track [Page 6]
