IFX Mail Archive: RE: IPP> Re: MOD - Confusion about image/tiff MIME Content Type

IFX Mail Archive: RE: IPP> Re: MOD - Confusion about image/tiff MIME Content Type

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

Hastings, Tom N (hastings@cp10.es.xerox.com)
Thu, 18 Feb 1999 15:46:05 -0800

Keith,

Thanks. So it looks like the IPP Model and Semantics 'mimeMediaType' value
of 'image/tiff' should point to the IANA Registry, not a particular RFC.

For future work and an extension to IPP to be developed in the IFAX over IPP
WG, we will need to solve the Interoperability Considerations problem called
out below where there are different profiles for TIFF.

Tom

Here is the updated IANA Registry entry:

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.

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

Intended usage: COMMON

Change controller: Stephen Zilles

>-----Original Message-----
>From: Keith Moore [mailto:moore@cs.utk.edu]
>Sent: Thursday, February 18, 1999 12:40
>To: Hastings, Tom N
>Cc: Larry Masinter; Lloyd McIntyre; Robert Buckley; Zilles, Steve;
>venable@wrc.xerox.com; Glenn.Parsons@nortel.ca;
>Jrafferty@worldnet.att.net; ipp; ifx@pwg.org; Keith Moore <
>Subject: IPP> Re: MOD - Confusion about image/tiff MIME Content Type
>
>
>Tom,
>
>I think that the IANA registration for image/tiff was fixed yesterday
>to point to the newer document.
>
>Keith
>