[Scribus] CMYK image processing
Tue Mar 21 20:50:47 CET 2006
Kai-Uwe Behrmann wrote:
> What are the right tools you expect an pixel editor should provide?
Well, first, I must be able to convert an image to CMYK. In that, I must
be able to tell Gimp how I want the channels to be separated. I need to
be able to choose which printing system I will be correcting for
(SWOP-coated, uncoated; Toyo inks; etc.), specify dot gain, and choose
which separation type I want to use (UCR or GCR), and specify ink
limits. The way Photoshop does this is just about perfect.
I wanted to compare how the Gimp manages color profiles to how Photoshop
does it, but I cannot find anywhere in the Gimp where you can specify
which profiles to use on an image. Ideally, we should be able to specify
default profiles for images, and whether or not Gimp should use the
embedded profiles. Again, PS is very good here.
In the 'Image > Mode' pull down there should be an option to convert to
a profile, any profile, from a pop-up option window. For example, if I
am correcting an image in my default RGB space (Adobe RGB) and I want to
convert an image to sRGB before I save it for use on the web I can do
this. Or if I am correcting an image that will be printed on different
types of media, I can correct it in my default CMYK space and convert
copies of it for newsprint or 4c silkscreen.
Something that Adobe has added to Photoshop that has been very useful
for me recently, are Spot channels. Say you have a grayscale image that
will overprint on top of a pantone color, you can create a CMYK document
and paste the grayscale image into the black channel. Then add a spot
channel that will print underneath it. In this way you can set up the
image exactly as you want it printed without having to rely on
InDesign's transparency settings. Save this image a a single-file DCS
and you're set. With this technique you could also add a silver ink to
the highlights on a saw or anything else metallic. I am sure you get the
It would also be nice to have a tool like the Selective Color tool that
Photoshop has. The other color correction tools for use with RGB look
good, but in the future the devs should really add the ability to use
the cc tools on adjustment layers.
Overall, I like the Gimp, but it just isn't quite ready for print
graphics yet. Aside from the lack of CMYK tools, it is just a slow app
to work in. It really needs a usability expert to go through and come up
with a better keyboard shortcut map that makes it quicker to select the
tools in the tools box and in the pull downs and add items that don't
have shortcuts, i.e. Select > Feather.
I hope this helps. I didn't mean to knock the Gimp, because there is a
whole lotta goodness in there. It just needs a little more love before
people are going to give up Photoshop for print work.
_End of line_
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