[Openicc] colord Printing Plans

[peters at skarpetis.com]

DeviceRGB should be left alone for the cases where the output is RGB. For other output colourspaces a default, such as sRGB, should be assigned. 

Peter Skarpetis

On 25/02/2011, at 7:39 PM, edmund ronald <edmundronald at gmail.com> wrote:

> Why would we wish to remap DeviceRGB to sRGB?
> WTF is going on here?
> Can somebody please make a flowchart of color policies that makes
> sense so we can all agree on some base rules?
> 
> Edmund
> 
> On Fri, Feb 25, 2011 at 12:14 AM, Gerhard Fuernkranz <nospam456 at gmx.de> wrote:
>> Am 24.02.2011 23:09, schrieb Chris Murphy:
>>> And in the case of RGB content being printed to a PostScript device, the content is color managed before it gets turned into PostScript.
>> 
>> When printing from dumb applications which are not color management
>> aware, this is unfortunately not the case. IMO most applications still
>> produce DeviceRGB Postscript files (actually "untagged" RGB, but as
>> there is no "UntaggedRGB" defined in Postscript, they use DeviceRGB
>> instead). A simple pass-through would either treat the DeviceRGB as
>> printer RGB (in case of a printer driver with RGB ProcessColorModel), or
>> result in an UCR-based DeviceRGB -> DeviceCMYK transformation in the
>> RIP, as defined by the PLRM, which is certainly not what we want either.
>> Somewhere these DeviceRGB colors still need to be remapped (e.g. to
>> sRGB) and transformed to the ICC-based printer color space.
>> 
>> So I'm wondering, what are arguments against generally supplying the
>> desired DefaultRGB/Gray/CMYK profiles, and the printer profile as output
>> profile to ghostscript, and then feeding gs either with the PS or with
>> the PDF document to be printed, in order to produce the raster file,
>> implicitly getting more or less full PS and PDF color management (except
>> for potential bugs/limitations still present in the current
>> implementation)? [still all options are open; DefaultCMYK can be of
>> course also set to /DeviceCMYK if printer CMYK passthrough is desired,
>> or one could set DefaultCMYK to say ISOcoated, for re-targeting PS and
>> PDF files intended for a press to the printer]
>> 
>> Regards,
>> Gerhard
>> 
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