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Network Working Group                                         G. ParsonsRequest for Comments: 3302                               Nortel NetworksObsoletes:2302                                              J. RaffertyCategory: Standards Track                          Brooktrout Technology                                                          September 2002Tag Image File Format (TIFF) - image/tiffMIME Sub-type RegistrationStatus 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 (2002).  All Rights Reserved.Abstract   This document describes the registration of the MIME sub-type   image/tiff.  This document refines an earlier sub-type registration   inRFC 1528.   This document obsoletesRFC 2302.1.  Conventions used 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 inRFC 2119 [REQ].2.  Overview   This document describes the registration of the MIME sub-type   image/tiff.  The baseline 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.org>.Parsons & Rafferty          Standards Track                     [Page 1]

RFC 3302                       image/tiff                 September 20024.  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 Jose, CA 95110-2704      Phone: +1-408-536-6000      Fax:   +1-408-537-6000   A copy of this specification can also be found in:http://partners.adobe.com/asn/developer/PDFS/TN/TIFF6.pdf   While a brief scope and feature description is provided in this   section 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 purpose 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.   Though TIFF is a rich format, it can easily be used for simple   scanners and applications as well because 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 several color spaces.      -  TIFF includes a number of compression schemes that allow         developers to choose the best space or time tradeoff for their         applications.      -  TIFF is designed to be extensible and to evolve gracefully as         new needs arise.Parsons & Rafferty          Standards Track                     [Page 2]

RFC 3302                       image/tiff                 September 2002      -  TIFF allows the inclusion of an unlimited amount of private or         special-purpose information.5.  MIME Definition5.1  image/tiff   The image/tiff content-type was previously defined inRFC 1528 as   containing TIFF 6.0 encoded image data, with specific reference made   to a subset 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" (section 6.2) to enable identification of   a specific subset of TIFF and TIFF extensions for the encoded image   data.5.2  Application parameter   There are cases where it may be useful to identify the application   applicable to the content of an image/tiff body.  Typically, this   would be used 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 subset 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 absence of the   application parameter indicates that the encoded TIFF image is   Baseline 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 user.   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 inRFC 2434.   An application parameter is a hint to the receiver.  It MUST NOT be   used as a blind request to execute some arbitrary program.Parsons & Rafferty          Standards Track                     [Page 3]

RFC 3302                       image/tiff                 September 2002   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.org      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 absence of the application parameter indicates that         the encoded TIFF image is Baseline 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 user.      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 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 useful to facilitate the viewing and         rendering of images by a recipient.  As such, the fields         currently defined in the TIFF 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 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, butParsons & Rafferty          Standards Track                     [Page 4]

RFC 3302                       image/tiff                 September 2002         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 presence 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 Jose, CA 95110-2704         Phone: +1-408-536-6000         Fax:   +1-408-537-6000         A copy of this specification can be found in:http://partners.adobe.com/asn/developer/pdfs/tn/TIFF6.pdf      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): .TIF         Macintosh File Type Code(s): TIFFParsons & Rafferty          Standards Track                     [Page 5]

RFC 3302                       image/tiff                 September 2002      Person & email address to contact for further information:         Glenn W. Parsons         gparsons@nortelnetworks.com         James Rafferty         jraff@brooktrout.com      Intended usage: COMMON      Change controller: James Rafferty6. 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 useful to   facilitate the viewing and rendering of images by a recipient.  As   such, the fields currently defined in the TIFF 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 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 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 fromRFC 2302   * Correction of magic number   * Improvements of the security considerations   * Change of change controller   * Various editorials to improve clarity8. References8.1 Normative References   [REQ]     Bradner, S., "Key words for use in RFCs to Indicate             Requirement Levels",BCP 14,RFC 2119, March 1997.Parsons & Rafferty          Standards Track                     [Page 6]

RFC 3302                       image/tiff                 September 2002   [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",BCP13,RFC 2048, November 1996.   [TIFF]    Adobe Developers Association, TIFF (TM) Revision 6.0 -             Final, June 3, 1992.8.2 Non-Normative References   [TIFFREG] Parsons, G., Rafferty, J. and S. Zilles, "Tag Image File             Format (TIFF) -image/tiff MIME Sub-type Registration",RFC2302, March 1998.   [TPC.INT] Malamud, C. and M. Rose, "Principles of Operation for the             TPC.INT Subdomain: Remote Printing -- Technical             Procedures",RFC 1528, October 1993.9. Authors' Addresses   Glenn W. Parsons   Nortel Networks   P.O. Box 3511, Station C   Ottawa, ON  K1Y 4H7   Canada   Phone: +1-613-763-7582   Fax:   +1-613-763-2697   EMail: gparsons@nortelnetworks.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.comParsons & Rafferty          Standards Track                     [Page 7]

RFC 3302                       image/tiff                 September 200210.  Full Copyright Statement   Copyright (C) The Internet Society (2002).  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.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Parsons & Rafferty          Standards Track                     [Page 8]

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