Tag Image File Format (TIFF) - image/tiff MIME Sub-type Registration
draft-ietf-fax-tiff-reg-05

Network Working Group                                    Glenn Parsons
  Internet Draft                                          James Rafferty
  Expires in six months                                   Stephen Zilles
                                                       February 13, 1998

               Tag Image File Format (TIFF) - image/tiff
                      MIME Sub-type Registration
                                   
                   <draft-ietf-fax-tiff-reg-05.txt>
                                   
  Status of this Memo
  
  This document is an Internet Draft.  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
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  ftp.isi.edu (US West Coast).
  
  Overview
  
  This document describes the registration of the MIME sub-type
  image/tiff.  The baseline encoding is defined by [TIFF].
  
  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>.
  
    

     Internet Draft                image/tiff             February 13, 1998

 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].
  
  
 2. 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/pdffiles/
  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.
  
  
 2.1 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.
  
  
 2.2 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.
     
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   - 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.
  
  
 3. MIME Definition
  
 3.1 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 subset known as TIFF Class F.  This document re-defines 
  the original image/tiff definition to refer to all of the profiles
  and extensions that build on 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 3.2) to enable 
  identification of a specific subset of TIFF and TIFF extensions 
  for the encoded image data.
  
  
 3.2 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.
  
         
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 4.  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.  . New 
          values should be defined in standards track RFCs and the 
          values should be registered with IANA, using the 
          registration form included in Appendix A.  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: 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.
  
          
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       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:
          ftp://ftp.adobe.com/pub/adobe/devrelations/devtechnotes/pdff
          iles/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
         Glenn.Parsons@Nortel.ca
  
         James Rafferty
         Jrafferty@worldnet.att.net
  
         Stephen Zilles
         szilles@adobe.com

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       Intended usage: COMMON
  
       Change controller:  Stephen Zilles
         
  
 5. Authors' Addresses
  
  Glenn W. Parsons
  Northern Telecom
  P.O. Box 3511, Station C
  Ottawa, ON  K1Y 4H7
  Canada
  Phone: +1-613-763-7582
  Fax:   +1-613-763-2697
  Email: Glenn.Parsons@Nortel.ca
  
  James Rafferty
  Human Communications
  12 Kevin Drive
  Danbury, CT 06811-2901
  USA
  Phone: +1-203-746-4367
  Fax:   +1-203-746-4367
  Email: Jrafferty@worldnet.att.net
  
  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:  szilles@adobe.com
  
  
 6. References
  
  [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.
  [TPC.INT] C. Malamud, M. Rose, "Principles of Operation for the
       TPC.INT Subdomain:  Remote Printing -- Technical Procedures",
       RFC 1528, 10/06/1993
  [TIFFPLUS] McIntyre, L., Zilles, S., Buckley, R., Venable, D.,
       Parsons, G., and J. Rafferty, "File Format for Internet
       Fax", Work in Progress, February 1998.
  [TIFF] Parsons, G., and J. Rafferty, "Tag Image File Format
      (TIFF) -- Application F", Work in Progress, February 1998

     
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  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 - (include 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 
    use of the new parameter should be defined here or in the 
    referenced standards track RFC.)  

   Person & email address to contact for further information:

   (fill in contact information)

   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.

     
     

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