[Openicc] Gutenprint team requests CM-off for a print queue be provided as a maintained engineering facility.

Michael Sweet msweet at apple.com
Fri May 11 15:25:40 PDT 2012


On May 11, 2012, at 2:17 PM, Chris Murphy wrote:
> ...
> There is no multitude of PDFs that are: PDF/X-3 + contain RGB output intent + contain /DeviceRGB objects. That's a very unique PDF, and I'd argue only occurs in a case where /DeviceRGB is "prematched" or otherwise intended to be left alone, as-is.
> For PDF's that do not contain an OutputIntent, are not PDF/X-3 compliant, fine. Second guess away, and treat /DeviceRGB with a substitute.

which is what CoreGraphics does...

> The Quartz PDF Context is certainly banning /DeviceRGB because to my knowledge it never causes such objects to be written into a PDF print spool file.

Today that is the case for any content produced by an application using the CG APIs.  That is because, in OS X 10.3 or so, Apple decided that using DeviceRGB for general rendering was a bad idea and changed the default device colorspaces to be GenericRGB and GenericGray, respectively.  This rippled into the generated PDFs so now if your app doesn't set a specific colorspace they get Generic instead, backed by the corresponding ICC color profile.

Of course, on Linux Cairo is generally used to create PDF content which (still? until recently?) uses DeviceRGB as well...

And then there are applications that produce PDF using DeviceRGB/Gray (HTMLDOC is one <hanging head in shame>).

Michael Sweet, Senior Printing System Engineer, PWG Chair

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