[Openicc] [Printing-architecture] [Gimp-print-devel] Colour

[Gerhard Fuernkranz]

Kai-Uwe Behrmann wrote:
> Am 16.11.09, 15:16 -0500 schrieb Chris Murphy:
>> On Nov 16, 2009, at 12:36 PM, Kai-Uwe Behrmann wrote:
>>
>>> There will be people who complain about the missed capability to hand tweak their colours. This is quite natural. A way to satisfy those demand is to support effect profiles, which fits well with the point above.
>>
>> Abstract profiles could do these kinds of edits in the PCS. Either as an advanced  panel of sliders that institute edits in the PCS - a sort of on-the-fly abstract class  profile. Or a separate means of creating them and just allow a pop-up menu of selections. I like the slider approach.
>>
>> I think it's important to not have effects baked into output device profiles.
>
> Can the effect profiles be applied in a late binding style - remotely after spooling?

Well, where and when in the pipeline is the rasterizing is done? Once
the document has been half-toned, it's rather impossible to apply color
transformations any more (i.e. in case the final raster data were spooled).

And applying an additional device -> PCS -> abstract -> PCS -> device
transformation in a *separate* post-processing step (after converting
the object colors to the color space associated with the printer's
process color model, but before half-toning) will certainly not help to
improve the overall accuracy of the color transformations, and some
colors may already have been clipped, which cannot be undone any more
afterwards by a de-saturation effect (though this clipping would have
been avoided if the de-saturation would have been applied before
applying the output profile). So I think the effects should be rather
incorporated into the color transformation chain from object colors to
the printer's process color model. Or alternatively, the intermediate
color space before applying the effects would need to be rather PCS.

Applying effects without integrating them into the profile seems also
difficult to me, if one intends to use pre-computed device link profiles
for the conversion from object colors to the printer's process color model.

Regards,
Gerhard