Network Working Group G. Parsons Internet Draft Nortel Networks J. Rafferty Brooktrout Technology Document: <draft-ietf-fax-tiff-regbis-00.txt> S. Zilles Category: Informational Adobe Systems, Inc. March 6, 2000 Tag Image File Format (TIFF) - image/tiff MIME Sub-type Registration <draft-ietf-fax-tiff-regbis-00.txt> Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 except that the right to produce derivative works is not granted. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet Drafts are valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet Drafts as reference material or to cite them other than as a "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 1. Abstract This document describes the registration of the MIME sub-type image/tiff. The baseline encoding is defined by [TIFF]. This document refines an earlier sub-type registration in RFC 1528 [TPC.INT]. Internet Draft image/tiff March 6, 2000 2. 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 in RFC-2119 [REQ]. 3. Overview This document describes the registration of the MIME sub-type image/tiff. The baseline encoding is defined by [TIFF]. 4. 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 <firstname.lastname@example.org>. 5. 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: ftp://ftp.adobe.com/pub/adobe/devrelations/devtechnotes/pdffi les/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. Internet Draft image/tiff March 6, 2000 5.1 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. 5.2 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. - TIFF allows the inclusion of an unlimited amount of private or special-purpose information. 6. MIME Definition 6.1 image/tiff The image/tiff content-type was previously defined in RFC1528 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. Internet Draft image/tiff March 6, 2000 6.2 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. 7. IANA Registration To: email@example.com 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. 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. Internet Draft image/tiff March 6, 2000 Encoding considerations: Binary or Base-64 generally preferred 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 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. 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 Internet Draft image/tiff March 6, 2000 A copy of this specification can be found in: ftp://ftp.adobe.com/pub/adobe/devrelations/devtechnotes/pd ffiles/tiff6.pdf Applications which use this media type: Imaging, fax, messaging and multi-media Additional information: Magic number(s): II (little-endian): 49 49 42 00 hex MM (big-endian): 4D 4D 00 42 hex File extension(s): .TIF Macintosh File Type Code(s): TIFF Person & email address to contact for further information: Glenn W. Parsons firstname.lastname@example.org James Rafferty email@example.com Stephen Zilles firstname.lastname@example.org Intended usage: COMMON Change controller: Stephen Zilles 8. References [REQ] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [MIME1] N. Freed and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, Innosoft, First Virtual, Nov 1996 [MIME4] N. Freed and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, Innosoft, First Virtual, Nov 1996. [TIFF] Adobe Developers Association, TIFF (TM) Revision 6.0 - Final, June 3, 1992. Internet Draft image/tiff March 6, 2000 [TPC.INT] C. Malamud, M. Rose, "Principles of Operation for the TPC.INT Subdomain: Remote Printing -- Technical Procedures", RFC 1528, 10/06/1993 9. Author's 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: email@example.com James Rafferty Brooktrout Technology 410 First Avenue Needham, MA 02494 USA Phone: +1-781-433-9462 Fax: +1-781-433-9268 Email: firstname.lastname@example.org Stephen Zilles Adobe Systems Inc. Mailstop W14 345 Park Avenue San Jose, CA 95110-2704 USA Voice: +1-408-536-4766 Fax: +1-408-536-4042 Email: email@example.com Internet Draft image/tiff March 6, 2000 Appendix A: IANA Registration form for new values of Application Parameter To: IANA@isi.edu Subject: Registration of new values for the Application parameter of image/tiff MIME type name: image/tiff Optional Parameter: Application New Value(s): Application=foo Description of Use: foo - (Ofoo0 is a fictional new value used in this message as an example, it is to be replaced with the new value being registered. Include a short description of the use of the new value here. This must include reference to a standards track RFC for the complete description; the use of the value must be defined completely enough for independent implementation.) Security Considerations: (Any additional security considerations that may be introduced by useof the new parameter should be defined here or in the referenced standards track RFC.) Person & email address to contact for further information: Glenn W. Parsons firstname.lastname@example.org James Rafferty email@example.com Stephen Zilles firstname.lastname@example.org INFORMATION TO THE SUBMITTER: The accepted registrations will be listed in the "Assigned Numbers" series of RFCs. The information in the registration form is freely distributable. Internet Draft image/tiff March 6, 2000 Full Copyright Statement Copyright (C) The Internet Society (2000). 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.