I am gluing some posts together:

Guillermo Espertino wrote:

>> It seems to me you completely misunderstood the whole thing. What  
>> makes
>> you think there is any CMYK -> RGB conversion involved here?
> I think he's talking about the procedure to perform when the source  
> file
> is CMYK. The proposal is to convert it to RGB (in the "what about CMYK
> files" section of the Peter's document).
> What if I want to touch up an image that a client sent me, already
> separated?

OK, I see that I was not clear enough in my blog:

"When further fine‐tuning for the printing press is the goal,
  then the solution is to shove the CMYK file straight into a
  press projection, as a static, pre-defined separation. Each
  plate is then still fully editable as outlined before."

what i tried to say is that users will have a choice to _not_
convert a CMYK file to RGB, but to load it straight into a
press projection. the resulting file will have an empty RGB part,
and a static base separation that comes straight from the file.
I fully intent here that GIMP will be able to set up the press
projection from the file, including the number of plates, their
colors used and their order. maybe users will have to help with
saying that spot plate #2 uses pantone 1234 (say).

so now we have the CMYK file as lossless as it gets in to GIMP,
every plate can be touched up, or a block of text added..., or
all plates together get a curves applied for more oomph, or...

the result can be saved again to a separation file.

Hal V. Engel wrote:

>>> When a received CMYK file is to be used in new creative work, we  
>>> already
>>> saw that ‘it needs to be imported and converted to RGB.’
> And I am not sure that this is the correct approach.  Why would this  
> be
> needed?  Is this so that we can deal with GIMPs limited  
> functionality to
> handle anything beyond RGB color spaces?  If so then the focus  
> should be on
> supporting other color spaces directly.

I forgot to write in my blog that besides

"When a received CMYK file is to be used in new creative work,
  we already saw that ‘it needs to be imported and converted to  

I see the whole process like taking a scanned image or an image from
a digital camera and include it in new creative work. similar to
those situations the MYK file import will need to be tuned up for
color balance and contrast before adding it to the creative work.

> I also have not any anything in the thread related to how color  
> management
> fits.   After all how do you create the printer specific separations  
> from an
> RGB (or other non-device specific) image into the correct device  
> values
> without involving the color management engine?

I did include that:

"Note also that the colors in the press projection are already
  slightly different than that of the normal view, because the
  color profile of the printing press is taken into account."

I am aware that color profiling is a very serious thing in
the world of printing presses.


         founder + principal interaction architect
             man + machine interface works

         http://mmiworks.net/blog : on interaction architecture

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