IPP> MOD - Confusion about image/tiff MIME Content Type

IPP> MOD - Confusion about image/tiff MIME Content Type

IPP> MOD - Confusion about image/tiff MIME Content Type

Hastings, Tom N hastings at cp10.es.xerox.com
Thu Feb 18 11:52:04 EST 1999


I'm confused and concerned about what the MIME Content Type 'image/tiff'
means and implies.

There is the IANA Registration from 1993 and there is RFC 2301 File Format
for Internet Fax.  RFC 2301 seems to define a lot more than the original
'image/tiff'.  Worse, the IANA registration entry does not cite RFC 2301.  

IPP uses MIME Content Types (MIME Media Types?) to indicate the format of a
document in a create job request (the "document-format" Job object
attribute) and for an IPP Printer to indicate what document formats it is
capable of printing (the "document-format-supported" Printer object
attribute).

Should the IPP mimeMediaType value in [ipp-mod] section 4.1.9 be listed as:

	'image/tiff':  Tag Image Format - see IANA MIME Media Type registry

or:

	'image/tiff':  Tag Image Format - see File Format for Internet Fax
[RFC2301]

or:

	'image/tiff':  Tag Image Format - see IANA MIME Media Type registry
and [RFC2301]

Thanks,
Tom


The IANA Registration for image/tiff MIME Media Type is:

>From mrose at dbc.mtview.ca.us Sat Jul 31 20:04:51 1993
To: iana at ISI.EDU
Subject: Registration of new MIME content-type/subtype
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Date: Sat, 31 Jul 1993 20:04:00 -0700
From: Marshall Rose <mrose at dbc.mtview.ca.us>
Content-Length: 491
Status: RO
X-Lines: 24

MIME type name: image

MIME subtype name: tiff

Required parameters: none

Optional parameters: none

Encoding considerations: base64

Security considerations: none

Published specification:  TIFF class F, as defined in:

      Tag Image File Format (TIFF) revision 6.0

        Developer's Desk Aldus Corporation
	411 First Ave. South Suite
        200 Seattle, WA  98104
	206-622-5500

or:

      Tile Format for Internet Fax
      <draft-ietf-fax-tiffplus-07.txt>


Person & email address to contact for further information:

	Glenn Parsons <Glenn.Parsons at Nortel.ca>


On the other hand a March 1998 RFC entitled "File Format For Internet FAX"
formally defines TIFF/FX as minimal, extended and lossless JBIG modes
(Profiles S, F, J) for black-and-white fax, and base JPEG, lossless JBIG and
Mixed Raster Content modes (Profiles C, L, M) for color and grayscale fax.
These modes or profiles correspond to the content of the applicable ITU-T
Recommendations. Files formatted according to this specification use the
image/tiff MIME Content Type.

So if an IPP Printer's "document-format-supported" attribute includes the
MIME Content Type (or is it MIME Media Type?) with a value of 'image/tiff',
does that mean that the IPP Printer supports all of the above
representations?  If so, how come the IANA registered MIME media type
doesn't mention RFC 2301?

ISSUE:  Should IPP refer to the IANA registration of 'image/tiff' or to RFC
2301 as the definition of what the 'image/tiff' value means in the
"document-format" attribute that a client can supply in a create job request
and that a Printer object uses to indicate the document formats that it is
capable of accepting and printing?

Here is the Abstract for RFC 2301:


Network Working Group                                       L. McIntyre
Request for Comments: 2301                            Xerox Corporation
Category: Standards Track                                     S. Zilles
                                                    Adobe Systems, Inc.
                                                             R. Buckley
                                                      Xerox Corporation
                                                             D. Venable
                                                      Xerox Corporation
                                                             G. Parsons
                                                       Northern Telecom
                                                            J. Rafferty
                                                   Human Communications
                                                             March 1998
                      File Format for Internet Fax


Abstract

   This document describes the TIFF (Tag Image File Format)
   representation of image data specified by the ITU-T Recommendations
   for black-and-white and color facsimile. This file format
   specification is commonly known as TIFF-FX. It formally defines
   minimal, extended and lossless JBIG modes (Profiles S, F, J) for
   black-and-white fax, and base JPEG, lossless JBIG and Mixed Raster
   Content modes (Profiles C, L, M) for color and grayscale fax. These
   modes or profiles correspond to the content of the applicable ITU-T
   Recommendations. Files formatted according to this specification use
   the image/tiff MIME Content Type.


Tom Hastings
(310) 333-6413


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From: "Manros, Carl-Uno B" <cmanros at cp10.es.xerox.com>
To: "Masinter, Larry <masinter at parc.xerox.com>" <masinter at parc.xerox.com>,
        "Hastings, Tom N" <hastings at cp10.es.xerox.com>, ipp <ipp at pwg.org>
Subject: RE: IPP> MOD - Ok to add 'image/tiff' and 'application/pdf' to IP
	P/1.1 Model document format list?
Date: Thu, 18 Feb 1999 11:47:20 -0800
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Larry,

I think we have a disconnect in this discussion, or else I don't know what
you are talking about - wouldn't be the first time :-)

The document-format parameter in the current IPP spec is just an indicator
of the overall capability, it never tried to give you all the details about
particular MIME parameters. If you want to discuss this as a fully fledged
solution to meet requirements for IFAX over IPP, please move that discussion
to the new ifx at pwg.org DL.

I don't want to introduce new complex features in IPP/1.1 to meet the IFAX
requirements, they should be left for a separate discussion on the ifx DL.
However, if we come up with some REAL simple solution like adding a new
attribute which gives the tiff-profile as complementary information I am all
for adding it to IPP/1.1.

Carl-Uno

> -----Original Message-----
> From: Larry Masinter [mailto:masinter at parc.xerox.com]
> Sent: Wednesday, February 17, 1999 6:41 PM
> To: Hastings, Tom N; ipp
> Subject: RE: IPP> MOD - Ok to add 'image/tiff' and 
> 'application/pdf' to
> IPP/1.1 Model document format list?
> 
> 
> I suggest that IPP/1.1 change, with regard to MIME types, from:
>  
> # The value MAY include a charset parameter, depending on the 
> # specification of the Media Type in the IANA Registry [IANA-MT]. 
> 
> to 
> 
> # The value MAY include any number of parameters, depending
> # on the specification of the Media Type in the IANA Registry 
> [IANA-MT].
> 
> Many media type registrations have both required and optional
> parameters. A MIME type which requires a parameter is meaningless
> without the parameter, and there are many other parameters other
> than 'charset'.
> 
> It is also true that most 'text' types allow a 'charset' parameter,
> and you can point this out if you want; the current wording, though,
> seems to imply that parameters other than 'charset' are not allowed,
> which would be wrong.
> 
> Larry
> -- 
> http://www.parc.xerox.com/masinter
> 
> 




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