[Printing-architecture] Make use of extended color spaces on IPP printers

Michael Sweet msweet at msweet.org
Sun May 9 01:24:27 UTC 2021


> On May 8, 2021, at 7:52 PM, Solomon Peachy <pizza at shaftnet.org> wrote:
> ...
> 1) It must be possible to tell the printer that the job is already in 
>    its native/preferred colorspace.  (It's called various things in 
>    UIs, such as "disable color correction" or "host-managed color")
> 2) The job *must* support embedding an arbitrary ICC profile

Not the Job.  The *Document*.

> ...
> With respect to (2), It seems the PWG raster format only defines a 
> handful of colorspaces via ColorSpaceEnum; eg DeviceRGB, sRGB, and 
> AdobeRGB.  This is a weakness vs JPEG or PDF (which allows arbitrary 
> profiles.  Can we rely on that ColorSpace field being set correctly?

First, yes.  We've been doing so for years, even with Ghostscript (which typically converts everything to sRGB).

Second, it isn't a weakness to support well-known RGB color spaces along with a device RGB color space.  Printers that only support PWG/Apple raster really don't offer much in the way of color management.  I've been working with a couple vendors of these printers to make use of the device RGB color space for wider gamut RGB printing, since none of them want to support CIE Lab because Lab is *too* wide a color space and they can't optimize for it.

Michael Sweet

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