[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

William A Wagner wamwagner at comcast.net
Wed May 21 16:26:36 UTC 2014

As Ira suggests, I believe that it is very difficult to “guarantee” successful override, considering the potential complexity and variations in the PDL.  But ‘attempted’ is squishy  and making it REQUIRED  might tempt some to report ‘attempted’ even when the attempt is halfhearted (or non-existent). That would make the value even more unreliable. Perhaps we should have allowed a value of ‘best effort’  meaning that the printer will really try. But I think making ‘attempted’ a minimum REQUIRED response may just increase uncertainty. Better that the User understand that he is stuck with what is in the PDL  if there is not  very good likelihood that  the overrides will be completely successful.


Bill Wagner


From: ipp-bounces at pwg.org [mailto:ipp-bounces at pwg.org] On Behalf Of Ira McDonald
Sent: Wednesday, May 21, 2014 11:42 AM
To: Kennedy, Smith (Wireless Architect); Ira McDonald
Cc: <ipp at pwg.org>
Subject: Re: [IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs


Hi Smith,

We've never made "pdl-override-supported" have 'guaranteed' as REQUIRED

(even in IPP/2.1 or IPP/2.2 levels), because it's binary.  

If you claim that your Printer supports 'guaranteed' then you have to be able to
*successfully* intercept and override everything in your interpreters (vanishingly 
unlikely in PDF, for example).


I agree with Mike that I've never seen a printer in the wild that actually supported


I also agree that should make 'attempted' a REQUIRED value and 'guaranteed'

a RECOMMENDED value (explaining in the Implementors Guide that there are

practical limitations w/ third-party interpreters to perfect override).


- Ira


- Ira

Ira McDonald (Musician / Software Architect)
Co-Chair - TCG Trusted Mobility Solutions WG
Chair - Linux Foundation Open Printing WG
Secretary - IEEE-ISTO Printer Working Group
Co-Chair - IEEE-ISTO PWG Internet Printing Protocol WG
IETF Designated Expert - IPP & Printer MIB
Blue Roof Music / High North Inc
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mailto: blueroofmusic at gmail.com
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On Wed, May 21, 2014 at 11:22 AM, Kennedy, Smith (Wireless Architect) <smith.kennedy at hp.com> wrote:

Hi Mike,

Since “attempted” is so squishy, why not mandate “guaranteed”?  Including “attempted” seems like a loophole.


    Smith Kennedy
    ATB Wireless Architect - PPS
    Hewlett-Packard Co.

On 2014-05-21, at 7:42 AM, Michael Sweet <msweet at apple.com> wrote:

> All,
> It has come to my attention that neither the IPP Everywhere nor the PWG Raster Format specs explicitly call out required values for the "pdl-override-supported" Printer attribute. This attribute specifies whether the Printer can override embedded job ticket information (such as media size) when requested in a Job via the "ipp-attribute-fidelity" or "job-mandatory-attributes" Job Template attributes.
> Generally speaking, Printers SHOULD support PDL override for the standard PDLs in IPP Everywhere, including PWG Raster, JPEG, and PDF.  Typically this means forcing prints to a single media/size or forcing simplex/duplex output, and is particularly important for JPEG.
> My recommendation is for us to add the following conformance statement in a future revision of the IPP Everywhere specification:
>    pdl-override-supported (type2 keyword)
>    When reporting capabilities for the 'application/pdf', 'image/jpeg', or 'image/pwg-raster'
>    MIME media types, Printers MUST report either 'attempted' or 'guaranteed' for the
>    "pdl-override-supported" Printer attribute,
> Thoughts?
> _________________________________________________________
> Michael Sweet, Senior Printing System Engineer, PWG Chair

> _______________________________________________
> ipp mailing list
> ipp at pwg.org
> https://www.pwg.org/mailman/listinfo/ipp

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