[Scribus] Making and using ICC profiles with Scribus

[Atlantic Tech Solutions]

On Sun, 2003-11-09 at 14:42, Christoph Schoenherr wrote:
> Dear Peter,
> 
> thanks for your advices. Please see my replies to your questions 
> below:

Your welcome. Sorry for the delay in repsonding. I've been away all day
at a conference. 
> 
>   -----------   snip  --------------------------------------- 
>  On Donnerstag, 6. November 2003 23:16, Atlantic Tech Solutions 
> wrote:
> 
> > On Wed, 2003-11-05 at 07:49, Christoph Schoenherr wrote:
> > > Dear all,
> > >
> > > I'm intending to get custom made profiles for my inkjet
> > > printer for use with Scribus. Has anyone got some experience
> > > with how to do that? The monitor is already profiled with a
> > > Spyder.
> >
> > Good. I am assuming you have color set to 6500K.
> >
> > > Most of the companies offering custom made profiles assume
> > > that one prints their test chart out of Photoshop, but can I
> > > do the same procedure with the test chart loaded as an image
> > > in Scribus?
> > >
> > > I'm using an Epson 1270 with Generations4 inks and
> > > Hahnem?hle PhotoRag watercolor paper, Scribus 1.0 with lcms
> > > on SuSE 8.1.
> >
> > Maybe. It depends if the image is RGB or CMYK.
> >
> It's RGB.
> 
> > The big difference is whether this printer is a real CMYK
> > printer or a RGB printer. RGB printer ? Yes, many inkjet
> > printer drivers expect to *receive* color info in sRGB and the
> > driver does the conversion to 3,4 or 6/7 inks automatically.
> >
> The printer is also RGB.
> 
> > However, if it is an RGB driver printer, it might be far
> > simpler to open the PSD or TIFF in the GIMP and print to that
> > with the special GIMP print drivers without any color
> > corrections - except noting the type of paper. The GIMP can
> > open Photoshop PSD's
> >
> Yes, that's true -- but then what am I going to do with a profile 
> based on GIMP output and not on output coming from Scribus?
> I've been told that it is most critical not to change the 
> workflow *at all* once the profile being made. Please correct me 
> if I'm wrong, and excuse my ignorance.

No you are correct as there is no real built in color managment module
in Linux desktop enviroments or Xfree86. Well, actully X has rudimentary
gamma adjustments which are usually set to no adjustment in the
settings. I've never played with this in X.

> As far as the GIMP is concerned, I don't see the possibility to 
> use an ICC printer profile with it yet.
> 
> > For CMYK printing in general:
> >
> > 1. Get lcms 1.11
> > 2. Upgrade Scribus to 1.1.2. It has enhancements to the color
> > correction of lcms, but you need 1.11 and Scribus 1.1.1+. This
> > is a new tweak - black point compentsation, which helps
> > adjusting contrast in photos.
> >
> > Were there any special instructions beside printing from
> > Photoshop ?
> >
> in brief, the advice is as follows:
> - open the test chart in Photoshop
> - switch off any color corrections in the printer driver
> - select the paper type (usually a matte paper)
> - in the color management section, set the "output color space" 
> to "Same as source" (usually Adobe RGB or sRGB)
> - print the file
> - have the printout measured
> - once you have got the profile, set "output color space" to this 
> profile and leave the printer driver as it were, with color 
> corrections switched off.

> So I was wondering if this would work in Scribus as well:
> - printing a test chart from Scribus with color management 
> switched off to get something like a "raw", unbiased output from 
> the printer
> - measuring the printout and making the profile
> - using this profile in Scribus with color management turned on 
> again, selcting this profile as printer profile

I would try this exactly as you outlined. Print without color management
enabled and in your printer settings in CUPS, there should be an option
for CMYK, RAW or color. You want color.

And the follow on advice to print with this profile and leave color
settings in the CUPS driver to neutral or no adjustments is correct,
Except for paper choice, as this affects ink density, which in turn
affects color output slightly. Pick the closest choice.

Now the funny thing I must say is in *certain* circumstances, you may
want to print without cms enabled if you are printing images with lots
of solid colors. Scribus does a good job of getting the screen to match
typical inkjet output with my inkjet with the CUPS-GIMP print drivers
and my HP inkjet.

Example:

I have a very hard time matching the Scribus logo colors on a 4 color
CMYK laser at my client's service bureau, especially the deep navy blue
in the logo. Yet, my simple HP inkjet and good paper can render them
perfectly. Actually, quite amazingly close on glossy paper. 

Why ?  My simple inkjet (and most inkjets with good paper) have a wider
gamma than a real CMYK printer. As I explained earlier, these printer
drivers expect RGB colors and do the conversion themselves. 

The other side of this is having a good printer profile is really
valuable in exact color matching screen to printer. With a correctly
profiled printer and accurately profiled monitor Scribus with littlecms
does a remarkably good job.

At my client's service bureau, one of their workstations is a dual boot
RH9/Win2k box. I profiled the monitor with Monaco's color tools, as well
as Gretag's color tools and a good spyder. Using those monitor profiles,
along with a correctly calibrated and profiled printer, the screen to
print match is really excellent in Scribus. The screen to print match is
*really* close.

This is new territory for Scribus and Linux in general, so do not
hesitate to pop back with more questions. I'll be very curious to see
the results after you get the profile back and do some test prints.

Regards,
Peter