[Scribus] Color Management issues [OFF-TOPIC]

[Hal V. Engel]

On Sunday 14 January 2007 16:14, jon wrote:
> > Am 14.01.07, 11:11 +0100 schrieb Tino Schwarze:
> >> On Sun, Jan 14, 2007 at 03:27:02AM +0100, jon wrote:
> >>> If you want to have better results you should convert any rgb to say
> >>> Adobe RGB (6500?K - but rel. large scale color space) or much better
> >>> ECI rgb (5000?K, large scale). This is for Europe only, though.
> >
> > ECI profiles are as much and as less for europe only as Adobe profiles
> > are
> > for north america only. What would say south america or australia ;-)
>
> Kai. Or Asia? Think it's all about standardisation? But isn't there
> a standard like all the US uses 6500? K (and SWOP) for reflectives and
> Europe uses 5000? K
> (and Euroscale) as a standard? Correct me.

Standardized and custom reflective input and output color spaces are almost 
always D50 at least in the US.  So cameras, scanners and printers are 
normally profiled for D50 capture or viewing conditions.  Monitor color 
spaces, including idealized monitor color spaces like AdobeRGB and sRGB, are 
mostly D65 color spaces at least in the US.  But it is possible to make 
profiles for other viewing conditions.  For example if you had a photo that 
you knew was going to be displayed under tungsten lighting (around 2700K) you 
can, with some profiling software, build a custom profile for 2700K viewing 
conditions so that the printer output appears as it should in that lighting.

>
> >> Thanks, I'll give it a try.
> >
> > Tino,
> > you dont need to convert to an intermediate colourspace for separating
> > to
> > Cmyk. Just convert from the image colour space to the destination
> > colour
> > space and you should be fine.
>
> Kai, we had a lot of false shifting issues with directly converting
> from sRGB (or AdobeRGB)
> to  cmyk (not really depending on intents) and we were always in the
> need
> to color correct transformed images after doing so. Intermediate
> conversion really solved
> some when not most of our problems - mostly. :-)
>
> But I am curious, do you have any advice belonging to this? That's not
> meant to be ironic in any way,
> but if you could be of any help, it's much appreciated.
>
> > Even though for editing, the above profiles are good choices, including
> > LStar-RGB.
> >
> >>> But with photographic images I commonly get the best results when
> >>> using
> >>> perceptual as rendering intend instead of relative shift (rel.
> >>> colormetric).
> >>
> >> The images are not photographic and some time ago, when I looked into
> >> CM
> >> the first time, I decided that rel. colorimetric was the way to go.
> >
> > The photometric intent is implementation dependent and thus not a
> > relyable choice for corporate colours (logos).
>
> Kai, think your are right with logos, but aren't any of the rendering
> intents implementation
> dependend? All my CM-Modules seem to operate slightly different from
> each other.
> Being a bit puzzled.
> Thanks, Jon
>
> > Colour shifts are possible.
> > Hence the often recommendation to relative colorimetric.
> > For photos the photographic intent gives often better results.
> >
> > Viel Spa?.
> >
> >
> > Gr??e,
> > Kai-Uwe Behrmann
> > --
> > Programmierung f?r Farbmanagement
> > www.behrmann.name + www.oyranos.org + www.cinepaint.org
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