[Printing-architecture] PWG Raster format (IPP Everywhere) not reliable

Michael Sweet msweet at msweet.org
Wed Nov 13 12:24:10 UTC 2019


As the PWG isn't in the business of enforcing standards, there isn't a whole lot the PWG can do except when the vendor has submitted their printer (self) certification results.  IPP Everywhere printer self-certification uses PWG Raster test documents, so if any of the printers in question show up on the IPP Everywhere printers page (https://www.pwg.org/printers) then the PWG can ask the vendor to provide a firmware update and/or remove the listing from the page pending a re-certification.

Currently only HP has submitted self-certification results to the PWG.  I know many other vendors have been working towards that, but so far no Brother, Canon, or Epson printer has been added to the IPP Everywhere printers page.

> On Nov 13, 2019, at 6:27 AM, Till Kamppeter <till.kamppeter at gmail.com> wrote:
> Hi,
> recently, I saw several bug reports where certain printer models advertise to understand PWG Raster but in fact are not able to print this format. Fortunately all IPP-Everywhere/Mopria/Wi-Fi-Direct printers also do AirPrint and so one can print in Apple Raster which reliably works.
> The bug reports are
> https://github.com/apple/cups/issues/5238
>   Create PPD file from get-printer-attributes
>   (Printer: Canon Pixma Pro 10)
> https://github.com/OpenPrinting/cups-filters/pull/168
>   Epson ET-7700 does not support image/pwg-raster
> https://github.com/OpenPrinting/cups-filters/issues/171
>   Attribute differences
>   (Printer: Epson Workforce WF-2630)
> All these got solved by modifying the PPD generators of CUPS and cups-filters so that if a printer supports both Apple Raster and PWG Raster that the printing gets done in Apple Raster.
> This bug report can have the same reason:
> https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1850127
>   Unable to print with Brother printer since upgrade to Ubuntu 19.10
>   (Printer: Brother HL-L8260CDW)
> It got solved by a printer firmware update and it is also not clear by the attached files whether it was actually tried to print in PWG Raster.
> This makes the impression that the implementation of PWG Raster support in many printers is buggy and so IPP Everywhere and generally driverless IPP printing standards using PWG Raster is not reliable. And PWG Raster was created as a free and open standard format for driverless printing.
> I think this should get escalated to the PWG and especially better verification methods for PWG Raster creation and consumption should get introduced, and firmware updates issued for existing printers.
>   Till
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Michael Sweet

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