IFX Mail Archive: RE: IFX> FW: [Comments on UIF spec]

IFX Mail Archive: RE: IFX> FW: [Comments on UIF spec]

RE: IFX> FW: [Comments on UIF spec]

From: McDonald, Ira (imcdonald@sharplabs.com)
Date: Thu Jun 28 2001 - 11:05:12 EDT

  • Next message: Hastings, Tom N: "IFX> IPP FAX telecon, Fri, June 29, 12-2 PDT (3-5 EDT); Review IFX spe c"

    Hi John,

    At yesterday's IPP Fax telecon, we discussed all of your comments.

    Brief replies to the best of my abilities are included in your note
    below, preceded by '<ira>'.

    Cheers,
    - Ira McDonald, consulting architect at Sharp and Xerox
      High North Inc

    -----Original Message-----
    From: McDonald, Ira [mailto:imcdonald@sharplabs.com]
    Sent: Wednesday, June 27, 2001 11:55 AM
    To: 'ifx@pwg.org'; Thomas, John; Whittle, Craig
    Subject: IFX> FW: [Comments on UIF spec]

    Hi folks,

    Here are comments from my colleague John Thomas at Sharp on UIF spec.

    We should consider them at this afternoon's telecon, if we have time.

    Cheers,
    - Ira McDonald, consulting architect at Sharp and Xerox
      High North Inc

    -----Original Message-----
    From: Thomas, John
    Sent: Tuesday, June 26, 2001 5:36 PM
    To: McDonald, Ira
    Cc: Thomas, John; Olbricht, Eric; Whittle, Craig; Koss, Scott; Murdock,
    Joe; Hurtz, Robert
    Subject: RE: IFX> IPP FAX telecon agenda, Wed, June 27, 10-12 PDT (1-3
    EDT)

    Ira -

    Most of my questions and observations are about Universal Image Format (UIF)
    specification.

    1) The text fields for "ImageDescription", "DocumentName", "Software" and
    "DateTime" all use ASCII encodings. As we have discussed in the past, this
    limits these fields effectively to US English. (Is there an encoding for the
    British pound symbol in 7-bit ASCII?). Is this an oversight, or is this
    because of UIF's TIFF-FX/ITU legacy?
    NOTE: IPP-Fax identifies the "native language", at least for notification.

    <ira>
    Adobe Baseline TIFF specified ASCII only and didn't provide a language
    tag or alternate charset facility. Too bad, but UIF docs MUST be strictly
    compliant Adobe Baseline TIFF.
    A note will be added to the UIF spec about this limitation.
    The companion IPP Fax spec will explicitly say that the (localized)
    IPP job attribute 'document-name' SHOULD be used in preference to
    the TIFF 'DocumentName' field.
    'DateTime' doesn't need to be localized (it's a document create timestamp),
    because it can be localized by a client without problem.
    <--->

    2) What is the intended use for the "DateTime" field? Creation date? If
    so, it would be nice if the specification stated this. If an image has a
    creation date, shouldn't it also have an author/copyright holder field?
    Yes, I know this would be easy to edit out, but that would be a felony.
    Right? :-)

    <ira>
    Yes - it's a document creation date/time.
    No - we cannot change the semantics of 'DateTime' to add author.
    <--->

    3) The UIF spec expects the name and revision of the authoring software in
    the "Software" text field. I assume this text is format-free? Human
    readable (that is, if you are an English speaking human). And while we are
    on the subject of "Revision", shouldn't the specification identify its own
    revision? This is a common technique to provide "future backward
    compatibility".

    <ira>
    This is Baseline TIFF legacy. Human-readable in some language that
    can be written in ASCII without any accented Latin characters.
    <--->

    4) Why do profiles C, F and J (optionally) allow centimeter resolution
    units, but profiles L and M only allow "inch" resolution units? TIFF-FX
    again? Again I ask, how would this specification change if the United
    States FINALLY went metric? Is there a reason to prohibit cross-unit
    compatibility like, for example, the computational cost of a good
    sub-sampling algorithm?

    <ira>
    There are some typos on your list above. The b&w TIFF-FX profiles allowed
    centimers or inches. The color TIFF-FX profiles used inches because
    that's what the engine builders did at the time the TIFF-FX profiles
    were specified. For interoperability, UIF will NOT relax this
    restriction - gateways to Internet Fax and ITU GSTN fax are high
    priority.
    <--->

    5) Do all (international) bitmap format standards order scan lines
    left-to-right and top-to-bottom? If not, is there a need for UIF to specify
    this order? This scan-line order inherited from the base formats (e.g.
    TIFF-FX)?

    <ira>
    Adobe Baseline TIFF specifies the scan lines order.
    <--->

    6) I prefer the presentation of compliance requirements in the IPP-Fax
    specification to that in the UIF specification. IPP-Fax makes it clear what
    is "receiver" responsibilities and what is "sender" responsibilities. UIF
    doe not.

    <ira>
    Improvements in specification of compliance requirements will be done
    in the UIF spec.
    <--->

    7) Line 152 of the IPP-Fax specification says: "Universal Interchange Format
    (UIF)". I think it should say "Universal Image Format (UIF)".

    <ira>
    Done - Tom Hastings has it in his edits list.
    <--->

    Please pass on to the appropriate authorities any of these thoughts which
    have any merit.

    Thanks.

    John
    jct@sharplabs.com



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