Color image printing and display applications where the data
resource used may depend upon detailed color handling
capabilities of the recipient.
Scanning applications where the data transferred may depend
upon the detailed color image generation capabilities of the
originator.
- Examples of typical use:
To describe rendering or scanning capabilities:
(& (CIELAB-L-min>=0)
(CIELAB-L-max<=100)
(CIELAB-a-min>=-75)
(CIELAB-a-max<=+75)
(CIELAB-b-min>=-85)
(CIELAB-b-max<=+85) )
To describe capabilities required by a document:
(& (CIELAB-L-min=20)
(CIELAB-L-max=80)
(CIELAB-L-min=-35)
(CIELAB-L-max=+55)
(CIELAB-L-min=-45)
(CIELAB-L-max=+65) )
- Related standards or documents:
CIELAB color space is defined in [19]
CIELAB use for fax is described in ITU T.42 [9]
- Interoperability considerations:
When describing a recipient's capabilities, the minimum and
maximum color component values that can be rendered should be
indicated by inequalities as shown in the examples above.
When describing a document, the actual minimum and maximum
color component values used should be indicated, as shown
above.
- Security considerations:
- Privacy concerns, related to exposure of personal
information:
Where feature matching is used to select content applicable
to the physical abilities of a user, unusual values for this
feature tag might give an indication of a user's restricted
abilities.
- Related feature tags:
color [3]
color-space [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.7 Image file structure
- Media Feature tag name(s):
image-file-structure
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.21
- Summary of the media features indicated:
This feature indicates a file structure used for transfer and
presentation of image data.
It does not indicate image data coding: that is described by
separate feature tags (image-coding, etc.).
- Values appropriate for use with this feature tag:
Token
TIFF-FX profiles TIFF-S
[7]: TIFF-F
TIFF-J
TIFF-C
TIFF-L
TIFF-M
(may be extended by further registrations,
to cover non-TIFF image file structures)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other print or display applications that
transfer image data.
- Examples of typical use:
See Appendix B of this memo.
- Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
This tag is intended to provide information about an image file
structure. Information about image data coding is provided by
other tags.
In the case of TIFF-FX image data, there are a number of image
file format constraints that are imposed by the various usage
profiles defined in RFC2301 [7]. The purpose of the 'image-
file-structure' feature tag is to capture those file format
constraints.
Registration of additional image file structure tags should
focus similarly on image file structure issues, not raw image
data compression and coding. As a guide, an image file
structure may contain image data coded in a variety of ways,
and carries information to describe that coding separately from
MIME content-type labelling, etc.
- Related feature tags:
image-coding [this document]
- Related media types or data formats:
TIFF-FX [7]
TIFF V6.0 (Adobe) [20]
- Intended usage:
Internet fax
Image scanning/rendering applications
- Author/Change controller:
IETF
A.8 Image data coding
- Media Feature tag name(s):
image-coding
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.22
- Summary of the media features indicated:
This feature tag indicates a form of image data compression and
coding used.
It identifies a generic image coding technique used, without
regard to any specific profiling of that technique that may be
applied. Values for this feature are generally applicable
across a wide range of image transfer applications.
This information is distinct from the image file structure and
MRC information conveyed by the 'image-file-structure' tags.
- Values appropriate for use with this feature tag:
Token MH
MR
MMR
JBIG
JPEG
(may be extended by further registrations)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
- Examples of typical use:
See Appendix B of this memo.
- Related standards or documents:
MH, MR: ITU T.4 [13]
MMR: ITU T.6 [14]
JPEG: ITU T.81 [16]
JBIG: ITU T.82 [17]
- Interoperability considerations:
To establish the correct conditions for interoperability
between systems, capabilities to handle the generic image
coding technique and the specific image coding constraints must
be established.
- Related feature tags:
image-coding-constraint [this document]
JBIG-stripe-size [this document]
image-interleave [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Image scanning/rendering applications
- Author/Change controller:
IETF
A.9 Image coding constraint
- Media Feature tag name(s):
image-coding-constraint
- ASN.1 identifier associated with these feature tags:
1.3.6.1.8.1.23
- Summary of the media features indicated:
This feature tag qualifies the 'image-coding' feature with a
specific profile or usage constraints.
Values for this feature are generally specific to some given
value of 'image-coding' and also to some restricted application
or class of applications.
- Values appropriate for use with this feature tag:
Token JBIG-T85 (bi-level, per ITU T.85)
JBIG-T43 (multi-level, per ITU T.43)
JPEG-T4E (per ITU T.4, Annex E)
(may be extended by further registrations)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
The specific values for this feature indicated above are
intended for use with Internet fax.
- Examples of typical use:
See Appendix B of this memo.
- Related standards or documents:
JBIG-T85: ITU T.85 [18]
JBIG-T43: ITU T.43 [10]
JPEG-T4E: ITU T.4 Annex E [13]
- Interoperability considerations:
To establish the correct conditions for interoperability
between systems, capabilities to handle the generic image
coding technique and the specific image coding constraints must
be established.
- Related feature tags:
image-coding [this document]
JBIG-stripe-size [this document]
image-interleave [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.10 JBIG stripe size
- Media Feature tag name(s):
JBIG-stripe-size
- ASN.1 identifier associated with these feature tags:
1.3.6.1.8.1.24
- Summary of the media features indicated:
This feature is a specific usage constraint that is applied to
JBIG image coding (image-coding=JBIG), and indicates the
allowable size for each stripe of an image, except the last.
A stripe of a JBIG image is a delimited horizontal band of
compressed image data that can be decompressed separately from
the surrounding data.
- Values appropriate for use with this feature tag:
Integer (>0)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
- Examples of typical use:
(JBIG-stripe-size=128)
(JBIG-stripe-size>0)
- Related standards or documents:
JBIG: ITU T.82 [17]
JBIG-T85: ITU T.85 [18]
JBIG-T43: ITU T.43 [10]
- Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
In the case of Internet fax, the specific constraints allowed
for a receiver are those given as examples above.
Specifying a stripe size that is not limited (JBIG-stripe-
size>0) means that an entire page of image data is encoded as a
single unit. This may place considerable demands on the memory
of a receiving system, as the entire stripe needs to be
buffered in memory.
- Interoperability considerations:
To establish the correct conditions for interoperability
between systems, capabilities to handle the generic image
coding technique and the specific image coding constraints must
be established.
- Related feature tags:
image-coding [this document]
image-coding-constraint [this document]
image-interleave [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.11 Image interleave
- Media Feature tag name(s):
image-interleave
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.25
- Summary of the media features indicated:
This feature indicates an image interleave capability.
It may be used with JBIG images (image-coding=JBIG) to indicate
color plane interleaving of either stripes or entire image
planes.
- Values appropriate for use with this feature tag:
Token Stripe
Plane
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
- Examples of typical use:
(image-interleave=stripe)
(image-interleave=[stripe,plane])
- Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
Specifying a plane interleave means that an entire page of
image data must be buffered in order to generate render the
image. This may place considerable demands on the memory of a
sending or receiving system.
- Related feature tags:
image-coding [this document]
JBIG-stripe-size [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.12 Color subsampling
- Media Feature tag name(s):
color-subsampling
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.26
- Summary of the media features indicated:
This feature tag indicates whether color information may be
subsampled with respect to luminance data.
It is used with continuous color images (color=full), color
spaces that use separate luminance and color components (e.g.
color-space=LAB), and image file structures that support color
subsampling.
- Values appropriate for use with this feature tag:
String "1:1:1"
This value indicates a full set of color
component samples for each luminance
component sample.
"4:1:1"
This value indicates a set of color samples
for each luminance sample.
(may be extended by further registrations)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Color image printing and display applications where the data
resource used may depend upon color handling capabilities of
the recipient.
Scanning applications where the data transferred may depend
upon the image generation capabilities of the originator.
- Examples of typical use:
(& (color=full) (color-space=[Device-RGB,CIELAB])
(color-subsampling=["1:1:1","4:1:1"]) )
- Related feature tags:
color [3]
color-space [this document]
image-file-structure [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.13 MRC availability and mode
- Media Feature tag name(s):
MRC-mode
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.27
- Summary of the media features indicated:
This feature is used to indicate the availability of MRC (mixed
raster content) image format capability, and also the MRC mode
available. A zero value indicates MRC is not available, a
non-zero value (in the range 1..7) indicates the available MRC
mode number.
An MRC formatted document is actually a collection of several
images, each of which is described by a separate feature
collection. An MRC-capable receiver is presumed to be capable
of accepting any combination of contained images that conform
to the MRC construction rules, where each such image matches
the separately declared resolution, color capability, color
model, image coding, and any other capabilities.
NOTE: an MRC formatted document may appear within a TIFF
image file structure.
Within an MRC-formatted document, multi-level coders are
used for foreground and background images (i.e. odd-
numbered layers: 1, 3, 5, etc.) and bi-level coders are used
for mask layers (i.e. even numbered layers 2, 4, 6, etc.).
- Values appropriate for use with this feature tag:
Integer (0..7)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
- Examples of typical use:
See Appendix B of this document.
- Related standards or documents:
ITU T.44 [15]
- Interoperability considerations:
To establish the correct conditions for interoperability
between systems, capabilities to handle the MRC mode and any
contained image coding techniques must be established.
- Related feature tags:
image-coding [this document]
MRC-max-stripe-size [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
A.14 MRC maximum stripe size
- Media Feature tag name(s):
MRC-max-stripe-size
- ASN.1 identifier associated with this feature tag:
1.3.6.1.8.1.28
- Summary of the media features indicated:
This feature may be used with MRC coding (MRC-mode>=1), and
indicates the maximum number of scan lines in each MRC stripe.
The value given indicates an upper bound on the stripe size.
The actual value may vary between stripes, and the actual size
for each stripe is indicated in the image data.
- Values appropriate for use with this feature tag:
Integer (>0)
- The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
Internet fax, and other applications that transfer image data.
- Examples of typical use:
(MRC-max-stripe-size=[0..256])
(MRC-max-stripe-size>=0)
- Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
For Internet fax, the legal constraints for an image receiver
are those given as examples above.
- Related feature tags:
MRC-mode [this document]
- Related media types or data formats:
TIFF-FX [7]
- Intended usage:
Internet fax
Color image scanning/rendering applications
- Author/Change controller:
IETF
Appendix B: TIFF mode descriptions
This appendix contains descriptions of the TIFF modes defined by RFC
2301 [7], presented as feature set expressions in the form defined by
"A syntax for describing media feature sets" [2] and using the
feature schema introduced by this document.
These may be taken as illustrations of the feature set combinations
that are required for the corresponding TIFF profiles described by
RFC2301.
(Tiff-S) :-
(& (image-file-structure=TIFF-S)
(color=Binary)
(image-coding=MH) (MRC-mode=0) )
(Tiff-F) :-
(& (image-file-structure=TIFF-F)
(color=Binary)
(image-coding=MH) (MRC-mode=0) )
(TIFF-J) :-
(& (image-file-structure=TIFF-J)
(color=Binary)
(image-coding=JBIG) (MRC-mode=0) )
(TIFF-C) :-
(& (image-file-structure=TIFF-C)
(color=Grey)
(image-coding=JPEG) (MRC-mode=0) )
(TIFF-L) :-
(& (image-file-structure=TIFF-L)
(color=Grey)
(image-coding=JBIG) (MRC-mode=0) )
(TIFF-M) :-
(& (image-file-structure=TIFF-M)
(color=[Binary,Grey])
(image-coding=[MH,JPEG]) (MRC-mode>=1) )
The feature sets described above are minimum requirements for the
corresponding TIFF modes. Thus, MR and MMR image coding are not
mandatory with TIFF mode F, and would be indicated by combining the
expression for (TIFF-F) with (image-coding=MR) and/or (image-
coding=MMR).
Similarly, limited, mapped or full color are not mandatory with the
grey/color TIFF modes (C, L and M), and would be indicated by
combining the corresponding expression with (color=limited),
(color=mapped) and/or (color=full).
TIFF profile M is a composite structure that can combine image data
coding options from other profiles: the description above indicates
mandatory features; other options may be indicated by combining
TIFF-M with other options (e.g. color= limited, mapped or full, and
image-coding= MR, MMR or JBIG).
Support for multiple TIFF profiles may be indicated by combining
their expressions with the OR operator; e.g.
(| (TIFF-F) (TIFF-S) (TIFF-J) )
indicates support for all black-and-white modes.
Appendix C: Revision history
00a 28-Sep-1998 Initial draft.
01a 12-Oct-1998 Incorporated review comments. Described feature
tag for differential x/y resolution ratio. Added
some examples.
01b 19-Oct-1998 Updated section 3.6 on image coding. Added
Appendix B containing feature expressions for the
TIFF modes from RFC2301.
02a 26-Oct-1998 Update examples. Add separate stripe size features
for JBIG and MRC.
02b 30-Oct-1998 Update examples. Add text clarifying the
description of MRC documents (as a set of feature
collections describing multiple contained images).
Add text describing constrains on resolution and
image coding usage within an MRC document.
02c 11-Nov-1998 Add ITU references. Added terminology: "capability
exchange", "capability identification" and
"capability description". Update JBIG and MRC
stripe size tags. Move subsampling to colour
section. Remove preferred-unit tag. Add T.4, T.6,
T.44 and T.81 references.
02d 16-Nov-1998 Update colour handling features, reflecting
proposed changes to the media features memo [3].
Update the image coding capability framework.
Updated TIFF mode descriptions in Appendix B.
03a 17-Nov-1998 Replace use of 'pix-x', 'pix-y' with 'size-x', '
size-y'. Add registrations in Appendix A.
03b 08-Dec-1998 Remove normative language and reference to RFC2119
(normative statements will be in the main fax
protocol draft). Revise structure of colour
features, and removed color-palette feature. Define
colour feature tags specific to CIELAB model and
colour space.
04a 14-Dec-1998 Update examples to reflect revised feature tags.
Revise description of MRC document in section 3.7.
Clarified interpretation of 'color=fixed'. Change
feature value 'color=fixed' to 'color=limited'.
05a 04-Jan-1999 Incorporate WG last-call comments: change
references to MRC-stripe-size to MRC-max-stripe-
size; similarly references to MRC-maximum-stripe-
size. Change "eifax" to "extended Internet fax".
Added guidance note for image coding feature usage.
Added IANA consideration comments to Appendix A.
05b 08-Jan-1999 Added new section for IANA considerations; removed
references to fax working group from registration
change control sections. Remove JPEG from TIFF-L
auxiliary predicate. Clarify description of MRC
receiver capabilities in section A.13. Remove '
color=full' from (TIFF-C) and (TIFF-M) predicates,
and add some explanatory text. Remove
'color=limited' from (TIFF-L) predicate.
05c 08-Jan-1999 Minor revisions to TIFF profile illustrations and
descripions in Appendix B. Reformatted description
of 'color=limited' in section 3.5 to clarify that
this does not indicate support for specific named
colors.
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