[scribus] How to use color management?

[Hal V. Engel]

On Friday 29 August 2008 04:13:10 am dwain wrote:
> On 8/28/08, Philipp Klaus Krause <pkk at spth.de> wrote:
> > So I want to try this color management stuff which claims to give me
> >  perfectly correct colors if I configure it correctly and will totally
> >  mess up everything if I don't (instead of keeping it deactivated so
> >  colors would just be mostly correct).

No colors will not be mostly correct with color management deactivated.  They 
will be sort of close sometimes and not so close most of the time.  The 
problem is that you will have no idea when they are close and when they are 
way off.

> >
> >  I want to send my files to a printer, which accepts PDF/X-3 and uses ISO
> >  12467-2 profiles (ISOcoated.icc/ISOcoated_v2_eci.icc, ISOuncoated.icc
> >  and ISOuncoatedyellowish.icc).

So you are using a printing service that expects your files be be one of the 
above formats?  If so then this part is simple and you don't need hardware for 
printer profiling usless you want to do proofs on your own printing hardware.

> >
> >  I have:
> >  - No calibration device
> >  - A RAL classic color chart
> >  - A monitor which has two settings ("warm" and "cold") and lets me
> >  alternatively set R,G,B on a 0-100 scale. It's currently set to "warm".
> >  - 7 color profiles on the download page of the monitor maker
> >  (http://www.belinea.com/de/service_support/fm/index.jsp?folderId=103863)

These may or may not be any good.  I do know that profiles I have tried from 
one of my monitor vendors where junk and I know that this is also the case for 
some other vendors.  But it may not be true for all vendors.  In other words 
the only way to know is to use a known good profile/calibratrion (which is 
only possible if you have access to a measurement device) and to compare the 
know good profile to the ones from the vendor.

Also profiles are specific to the whole processing chain used.  For fideo 
devices this includes the drivers used by the video card.  So you will likely 
need different profiles for Windows than for an X11 system.

> >
> >  What should I do to get correct color (change monitor settings? create
> >  profiles? use profiles from manufacturer? which one?)? 

For monitors it is now possible to get fairly inexpensive 
calibratrion/profiling measurement hardware.  For example you can get an X-
Rite Huey for about $50 plus shipping on ebay (this is for a new device).  
This hardware is supported by both ArgyllCMS and LProf (CVS) so those running 
on open source platforms can use this hardware.  Using hardware like a Huey 
you can adjust your monitor controls, calibrate your video card LUT and create 
custom profiles without too much difficulty.  Once this is done you can have a 
level of confidence in what you are seeing on your screen that is not 
otherwise possible. 

> >  Which options
> >  should I use for pdf export (especially in the color tab)?
>
> hi phillip,
> all of the color profiles must be the same on all of yoursoftware and
> hardware, 

Nonsense your profiles MUST be hardware specific for color management to work.  
Each piece of hardware needs to be characterized (have a hardware specific 
profile) so that the CMS knows how to handle it's colors.  If you use the same 
profile for everything then you have in affect turned color management off.

> except for your camera, but you can assign the profile if
> you have photoshop.
>
> i too do not have any calibrating equipment, but i have found that if
> software and hardware have the same color profiles you are in the ball
> park.  

In the ball park of what?

> i have a viewsonic vp171b that i have an srgb profile with no
> black point compensation set as the profile.  the rest of my hardware
> carry the same profile.

Again in this case you have disabled color management. 

>
> i use the user settings with the rgb respectively set at 50% for a
> middle gray.  no problems so far.  you could go the calibrator route,
> but you have had some good suggestions so far.  as a monitor ages it
> needs to be calibrated more often.

No not more often with age.  As monitors age (at least for CRTs) calibration 
becomes more important since the phosphors wear out and change with use.  For 
CRTs calibration should happen at least once a month and once a week is 
perhaps a little better.  For LCD monitors things are more stable which means 
you can use longer intervals between calibrations.

>
> this profile is recommended by the international color consortium for
> on screen viewing.  

They do?  Where is this recommendation located?

> here's the starting point to get the profile:
> http://www.color.org/resourcemain2.xalter
>
> i use a commercial printer who prints digitally from pdf files.  he
> told me that he can get the color right whether i send a rgb or cmyk
> or mixed (gasp) color file.  i have given him all three and what i see
> on my monitor is what comes off the press (printer).

This is called luck.  Most of his devices are close to sRGB and in the process 
of creating pdf files for the printer most of the conversions done by the CMS 
are close to correct.  Again this is because he is lucky rather than becaue 
his setup is correct.

>
> have fun with your new hobby -- color management.
>
> cheers,
> dwain

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