Re: [Gimp-print-devel] Strategy for profiling Epson R280 with Ultrachrome K3 inks

[Marko M. <mar...@gm...>]

On Fri, Aug 8, 2008 at 3:50 PM, Hal V. Engel <hv...@as...> wrote:
> On Friday 08 August 2008 12:07:58 pm Marko Milisavljevic wrote:
>> I will use ArgyllCMS first for RGB profiling to get a hang of that
>> software, but I would like to eventually do CMYK profiling. How did
>> you actually go about figuring out appropriate GCR settings in
>> ArgyllCMS? Any advice beyond what is written here:
>> http://www.argyllcms.com/doc/Scenarios.html#PP6
>
> That is about all that is available on this subject. Basically you want as
> much K as possible in the grays consistant with having a smooth K tone curve
> and no artifacts because of the K channel. This is highly dependent on the
> printer. For printers like the R2400 that have LK and LLK you will likely
> want to use more of the composit K channel for mid and light grays. But for
> printers with only a K cart you need to transition from mostly K to mostly
> process gray farily early to avoid K channel artifacts.

Thanks for that clarifying influence of LK & LLK - since I adapted
R2400 files to R280+pigment, that means that I should really modify
resulting media/....xml file; it is pretty aggressive with GCR for as
long as I profile in RGB. Lightroom only allows choice of RGB profiles
when doing "managed by application" color management which is why it
is nice to have a servicable RGB profile, although I suppose with
definition of my own paper types and proper assignment of profiles
through colorsync utility, it should successfully print to
CMYK-profiled printer where this conversion is colorsync managed.

Marko