[Scribus] implementing a CMYK workflow scenario with Gimp and Scribus

[unknown]

Hi,

Sometime ago I asked some questions on how a CMYK workflow could be achieved
with OSS tools and how to replace the "default" Phothoshop conversion. The
conclusion from the answers on the list was "there is no such thing as default
conversion". So I looked further.

Current scenario that works:

1- Photographer takes pictures (result is an RGB JPEG)
2- Pictures are edited for color, brightness, etc on PS and saved again (RGB
JPEG)
3- Another person opens the pictures on PS, changes some more parameters,
crops, cuts and converts to CMYK using the following profiles:

RGB: sRGB IEC61966-21
CMYK: Euroscale Coated v2

(these are actually the default settings for this version of PS)

Converted image is both stored as PSD and exported as EPS with PS.

4a - CMYK EPS is imported to QXP, which then generates Postscript, then
converted to PDF via extra tools
4b - CMYK PSD is imported to Scribus which generates directly PDF. Colour
management is NOT activated.

5 - PDFs from 4a and 4b look exactly the same, so Scribus is well integrated
on the current workflow.

Now, how to replace PS by the Gimp on step 3?

I have installed this plugin:

http://www.blackfiveservices.co.uk/separate.shtml

along with Adobe ICC Profiles.

The results are as follow:

Original image:

Loading Image...

Tiff exported from the Gimp:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-CMYK.tif

Scribus sla with imported image:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus/source/sweet_scribus.sla.gz

PDF generated with Scribus (colour intended for Printer, Colour Management NOT
active):

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus/sweet_scribus.pdf

PDF generated with QXP+Distiller:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-qxp/sweet_qxp.pdf

The printed results (on a laser printer) look quite similar.

Can someone comments on the quality/correction of this workflow?

One complaint of mine is that the Gimp CMYK plugin turns a 758K jpg into a
32MB tiff.

Best regards
Gustavo

[unknown]

Post by unknown
RGB: sRGB IEC61966-21
CMYK: Euroscale Coated v2

This is what some may term Default, but others may call it prefered.
In Photoshop, this is not the default. Photoshop defaults to using
Adobe RGB as default RGB profile.

On the same hand, you have a term "prefered" or "recommended" and this
is true only for Europe where Euroscale Coated v2 (or FOGRA) is the
most common CMYK profile.

So, as others have already said many times, there is no such thing as
a Default if you look at the industry as a whole. Individual software
may already have some Default settings (like Photoshop's Adobe RGB and
US Web Coated SWOP, or whatever it is called anyway). IOW, there are
only software defaults, industry recommendations, and last but not
least, individual designer's / prepress operator's preferences.

Individual preferences describe the techniques and methods that work
for some, and it depends on their experience. I know of a person who
actually adjusts brightness / contrast / RGB gain of his monitor based
on proofs from a printer and works without utilizing ICC profiles.
This method works for him. Others may prefer a perfectly
profiled/calibrated monitors and using ICC profiles. It all depends on
what works best for you.

Apart from this phylosophical babbling by myself, I guess your problem
is much simpler if you avoid using sensitive and ill-defined terms
such as "default conversion".

With GIMP 2.3.14, it is possible to open an image with embedded ICC
profile and use some form of color management, but only in RGB space.
There is also a plugin called Separate, which can convert an image
into CMYK space using input and output ICC profiles. Basically, you
can edit an image in RGB space by choosing an sRGB working profile and
choosing to convert an image to sRGB when you open it. The image can
then be converted to Euroscale Coated v2 if you have the profile, and
using Separate.

As a side note, Separate can create a simulated CMYK image (using some
layer transparency tricks) and *cannot* be easily edited in CMYK mode.
The separated file can be saved as XCF for later edits, or exported as
color-managed CMYK TIFF image for use in Scribus.

The resulting TIFF can be imported into Scribus.

The only downside of GIMP's own CMS is that it doesn't support black
point compensation, so some darker images will look... well... awful
in Print simulation mode. Also, the output of Separate plugin and
GIMP's print simulation is not the same. They differ a lot. However,
Separate is considered fairly accurate.

Another image editing tool on Linux is Krita. It supports full color
management in 16-bit per channel, but its editing capabilities aren't
that great. You can, of course, edit the image in GIMP and convert it
to CMYK using Krita. But that will not always work, because Krita is
not so reliable (at least in my modest experience with Krita).

Another way is to just save the image as RGB, and import it straight
into Scribus. Scribus will then convert the image into CMYK space at
PDF export if you chose to do so.

BR

Branko

[unknown]

Hi Gustavo,

Post by unknown
Sometime ago I asked some questions on how a CMYK workflow could be achieved
with OSS tools and how to replace the "default" Phothoshop conversion. The
conclusion from the answers on the list was "there is no such thing as default
conversion". So I looked further.
1- Photographer takes pictures (result is an RGB JPEG)
2- Pictures are edited for color, brightness, etc on PS and saved again (RGB
JPEG)
3- Another person opens the pictures on PS, changes some more parameters,
RGB: sRGB IEC61966-21
CMYK: Euroscale Coated v2
(these are actually the default settings for this version of PS)
Converted image is both stored as PSD and exported as EPS with PS.
4a - CMYK EPS is imported to QXP, which then generates Postscript, then
converted to PDF via extra tools
4b - CMYK PSD is imported to Scribus which generates directly PDF. Colour
management is NOT activated.
5 - PDFs from 4a and 4b look exactly the same, so Scribus is well integrated
on the current workflow.
Now, how to replace PS by the Gimp on step 3?

Just don't save the image as CMYK from GIMP, but use tifficc for that
purpose. While Scribus could do the RGB->CMYK conversion (color managed
if CM is active), my results differed (as of 1.3.3.7) from converting
using tifficc. There should also be a jpegicc, so you won't have huge
images at the end; tifficc supports Deflate compression well, so this
is the workflow of my choice:

- retouch image in Gimp (you'll stay in sRGB space, so your control is
pretty limited compared to Photoshop editing CMYK)
- save as RGB TIFF with Deflate option
- use tifficc -t1 -b -c2 -i sRGB.icc -o EuroscaleCoated.icc
- embed in Scribus

HTH,

Tino.

[unknown]

Gustavo Homem wrote...

Post by unknown
http://www.blackfiveservices.co.uk/separate.shtml
along with Adobe ICC Profiles.
The printed results (on a laser printer) look quite
similar....
Can someone comments on the quality/correction of
this workflow?

Hi Gustavo:

Following this post:

http://nashi.altmuehlnet.de/pipermail/scribus/2007-February/022317.html

I changed our workflow. We no longer use the separate
plug-in. We do use colour management in Scribus, using
the ICC profile ISOnewspaper30v4. We export to PDF
1.3.

There didn't seem to be any noticeable decline in
quality.

Here's a PDF where the images - including the adverts,
which are all created in The Gimp - underwent CMYK
separation through the Separate plug-in:
http://www.southsidemedia.org/page3.pdf

And here's one where RGB JPGs were used, with active
colour management in Scribus:
http://www.southsidemedia.org/page3_2.pdf

We were happy enough to decide to stop using Separate.

All the best,

David



___________________________________________________________
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[unknown]

Hi,

Post by unknown
I changed our workflow. We no longer use the separate
plug-in. We do use colour management in Scribus, using
the ICC profile ISOnewspaper30v4. We export to PDF
1.3.
There didn't seem to be any noticeable decline in
quality.
Here's a PDF where the images - including the adverts,
which are all created in The Gimp - underwent CMYK
http://www.southsidemedia.org/page3.pdf
And here's one where RGB JPGs were used, with active
http://www.southsidemedia.org/page3_2.pdf
We were happy enough to decide to stop using Separate.

I have now tried colour management on 1.3.3.8 and seem to get comparable
results, so far:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus-cm/

At first I didn't realize the I had to check the "Use ICC profile" option on
the PDF generation. The tooltip says it's used for embedding a profile into
the images, but if the option is not checked the colours seem to go wrong...

Best regards
Gustavo

Post by unknown
All the best,
David
___________________________________________________________
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Scribus at nashi.altmuehlnet.de
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[unknown]

Post by unknown
Hi,

Post by unknown
I changed our workflow. We no longer use the separate
plug-in. We do use colour management in Scribus, using
the ICC profile ISOnewspaper30v4. We export to PDF
1.3.
There didn't seem to be any noticeable decline in
quality.
Here's a PDF where the images - including the adverts,
which are all created in The Gimp - underwent CMYK
http://www.southsidemedia.org/page3.pdf
And here's one where RGB JPGs were used, with active
http://www.southsidemedia.org/page3_2.pdf
We were happy enough to decide to stop using Separate.

I have now tried colour management on 1.3.3.8 and seem to get comparable
http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus-cm/
At first I didn't realize the I had to check the "Use ICC profile" option on
the PDF generation. The tooltip says it's used for embedding a profile into
the images, but if the option is not checked the colours seem to go wrong...

Hi Gustavo,

Please make sure of this. Try to follow exactly the info provided by the
dialog and the tooltip and if you feel the tooltip is incorrect or
incomplete, please browse the bug report and if you can't find this
issue has been reported yet, then file a bug on that.

Tooltips must be helpful. Otherwise they need to be fixed.

Thanks!

Louis

Post by unknown
Best regards
Gustavo

Post by unknown
All the best,
David
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Scribus at nashi.altmuehlnet.de
http://nashi.altmuehlnet.de/mailman/listinfo/scribus

[unknown]

Hi,

Post by unknown
Hi Gustavo,
Please make sure of this.

I am sure that:

- The tool tip says "Embed a colour profile for images"
- If the option is unchecked the resulting PDF is very different from the ones
I got via:

GIMP+Separate+Scribus_without_cm

or

GIMP+Separate+Quark XPress

Post by unknown
Try to follow exactly the info provided by the
dialog and the tooltip and if you feel the tooltip is incorrect or
incomplete, please browse the bug report and if you can't find this
issue has been reported yet, then file a bug on that.

I can do that, but perhaps someone could explain first what's the purpose of
the Use ICC profile options, and what's the difference between checking them
and not.

Post by unknown
Tooltips must be helpful. Otherwise they need to be fixed.

Agree. These one seems confusing.

Best regards
Gustavo

Post by unknown
Thanks!
Louis

Post by unknown
Best regards
Gustavo

Post by unknown
All the best,
David
___________________________________________________________
The all-new Yahoo! Mail goes wherever you go - free your email address
from your Internet provider. http://uk.docs.yahoo.com/nowyoucan.html
_______________________________________________
Scribus mailing list
Scribus at nashi.altmuehlnet.de
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[unknown]

What i can see in the samples is that the result looks much more darker
and would have more after being printed too. i'm not sure i prefre
separate aspect but there is a real difference.

[unknown]

Hi,

Post by unknown
What i can see in the samples is that the result looks much more darker
and would have more after being printed too. i'm not sure i prefre
separate aspect but there is a real difference.

We now have 4 samples for comparison:

1.
RGB -> Gimp -> CMYK TIFF (Separate) -> Scribus (colour intended for Printer,
Colour Management NOT active):

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus/sweet_scribus.pdf

2.
RGB -> Gimp -> CMYK TIFF (Separate) -> Qxp -> Distiller:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-qxp/sweet_qxp.pdf

3.
RGB -> Scribus with Colour Management

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-scribus-cm/

4.
RGB -> Photoshop -> EPS -> Qxp:

http://people.angulosolido.pt/~gustavo/scribus/cmyk-workflow/sweet-ps-qxp/

Printed on a Laser printer, 3 seems to be the best match for the current
workflow (which is 4).

Comments?

Best regards
Gustavo

Post by unknown
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Scribus mailing list
Scribus at nashi.altmuehlnet.de
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[unknown]

Post by unknown
3.
RGB -> Scribus with Colour Management

I don't know about QXP workflow but this is what I use, and it gives me
excellent results.

Best regards,

Branko