[Scribus] Question regarding color management
Hal V. Engel
Fri Jul 14 18:44:37 CEST 2006
On Friday 14 July 2006 00:03, Kai-Uwe Behrmann wrote:
> please check if your rendering intent is eighter set to photografic or
> relative colorimetric with black point compensation activated.
> As well AdobeRGB is rather large. You will not be able to convert any
> colours near the RGB primaries (red, green, blue) into ISOcoated without
> gamut compression (partitial desaturation).
To expand on this some more. AdobeRGB has a medium large gamut covering about
50% of Lab gamut. Most monitors have gamuts that are significantly smaller
than this (typically 30% to 40% of Lab) with CRTs having somewhat smaller
gamuts than do the better LCDs. A typical CRT is very close to sRGB, which
covers about 35% of Lab gamut and is considered a small gamut color space.
LCDs typically have a larger gamut but a gamut that is still significantly
smaller than AdobeRGB.
The up shot of this is if you are going to use a generic profile for your
monitor sRGB is probably your best choice and in almost all cases AdobeRGB is
a poor choice. A better approach would be to get a profile from the monitor
manufacturer, good luck as most will act like you just arrived on a
spaceship when you ask them about this. And best is to get the hardware and
software to create custom profiles for your monitor.
Hardware and software to create custom monitor profiles used to be fairly
expensive ($250 +) but a few months ago GretagMacbeth (now part of X-Rite)
introduced a device called the Huey which is marketed under the Pantone name.
I have seen these on eBay for as little as $50 including international
shipping. This includes both Windows and Mac software. So Windows and Mac
users no longer have the "it's too expensive" excuse for not having custom
monitor profiles. Less costly solutions for Linux are being worked on at
this time but it will likely be some time before there is support for the
Huey hardware since Linux drivers or low level interface specifications are
not available for the Huey at this time.
> Lightness will be changed for the high lights and dark areas. Thats due to
> the ISOcoated gamut as well. You can see the gamut here:
> To mark the moved colours in your picture try mark_out_of_gamut or
> similiar option.
> Kai-Uwe Behrmann
> + development for color management
> + imaging / panoramas
> + email: ku.b at gmx.de
> + http://www.behrmann.name
> Am 14.07.06, 08:02 +0200 schrieb Matthias Schmitt:
> > Hello,
> > I am working with Scribus 1.2.3 on Mac OS X and really love this
> > program. As I am not a DTP expert I have tried to understand the
> > principles of color management, but I am still confused.
> > My document looks fine on the monitor. Color Management is activated
> > using Adobe RGB (1998) for pictures, solid colors and monitor. For the
> > printer I am using Europe ISO Coated FOGRA27, which I hope is fine for
> > printing in Europe. Once I active the option "Simulate Printer on the
> > Screen" all colors shift and look pale.
> > When I am exporting the PDF, once in RBG and once in CMYK, I can see a
> > similar color difference between those files on the screen using my PDF
> > viewer. What kind of file should I forward to the printing company?
> > Does this color difference indicate, that something is going wrong and
> > my print will not work?
> > Thank you for any help you can give me.
> > Greetings from Luxembourg
> > Matthias Schmitt
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