On Sat, 2003-10-04 at 01:07, francis tohill wrote: > This can sometimes occur if the placed image is RGB, the PDF will produce a > very washed out result when it converts to CMYK. > I've had this problem happen even with quark. If that's not the problem I > don't know what's happening there.
<snip> This is also true. And the key word here is *sometimes*. Why some and not others. The color shifts will be most pronounced in colors in RGB which are not easily reproduced in CMYK - deep blues, saturated greens. When Scribus performs the conversion it rightly does some GCR adjustments. I do recommend updating to lcms 1.11, as it has additional abilities with black point adjustments, which Scribus will recognize and use. Regards, Peter > > ----- Original Message ----- > From: "Peter Linnell" <scribusdocs at atlantictechsolutions.com> > To: "Sunil Joshi" <pavansut at comcast.net> > Cc: <scribus at nashi.altmuehlnet.de> > Sent: Saturday, October 04, 2003 2:30 PM > Subject: Re: [Scribus] Re: Color issues in 1.1.0 > > > > On Fri, 2003-10-03 at 23:39, Sunil Joshi wrote: > > > All: > > > Elsewhere Martin had described some issues with colors of graphics in > > > 1.1.0 on Mac version of Scribus. While that is indeed the case, I have > > > noticed a different problem. I am noticing that when I export a > > > document as pdf, the colors are washed out. Eg. here is a screen shot > > > > > > http://www.suniljoshi.netfirms.com/scribus/picture2.jpg > > > > > > of the print preview function of scribus on the left side, and the > > > acrobat file of the same page on the right side. The brilliant greens > > > and yellows have been completely washed out in the pdf file on the > > > right side. I wonder if any one else has seen this issue. > > > > > > -Sunil > > > > > > > This can be where you are using "printer" as a destination in exporting > > a PDF and then judging on screen in Acrobat Reader. Using "printer" as a > > destination will convert all RGB colors to CMYK upon export. > > > > Why? Acrobat Reader - even on Linux has does some color management > > adjustments to PDF's which have CMYK colors, which is probably the case > > here. > > > > The only time this is not true is if you have embedded or "tagged" the > > PDF with ICC profiles. In this case Acrobat will honor the tag and > > adjust accordingly, usually resulting in a much more accurate preview. > > > > Both Franz and I have observed this with both Scribus files. I have > > observed the same with PDF's which I have created in Indesign2 which I > > fully enabled CMS throughout the process from PS6 and Illy > ID2 > > > exported PDF. These PDF's are created on pro-level DTP gear which is > > hardware profiled and calibrated - thus screen to print match with > > correct settings is dead on. Yet, I still see the same "muting" of > > colors in both Acrobat and Acrobat Reader. > > > > The result is untagged CMYK will appear muted when viewed in Acro > > Reader. GS View and other viewers will reconvert to RGB and give a false > > impression. > > > > Note - this is important, the preview in Scribus is an RGB PNG generated > > from raw postscript via Ghostscript. Now, I think the print previewer is > > excellent, especially as it is derived from real postscript output and > > no other DTP app has this, it cannot be trusted 100% for judging colors, > > especially, judging from your screen caps, that you are pushing the edge > > of CMYK gamut. > > > > Now if you are viewing this in full Acrobat, it could be color > > management is disabled or set with the wrong profiles. > > > > Now that is the theory and mechanics of CMS... > > > > Observations/Questions: > > > > In your case, are you creating the colors in CMYK from the start ? > > > > Have you created any kind of profile for your monitor using the > > ColorSync wizard ? Without a color profile of any kind - all bets are > > off for judging color based on the screen preview. > > > > If these labels are intended for commercial printing, get the Adobe > > profiles linked in the docs and use US SWOP on uncoated stock as a > > starting point as your CMYK profile. That is a safe starting point. > > > > If you intend to print these to an ink jet, keep your colors in sRGB and > > export with "screen' as a destination. This is because most ink jet > > printers although CMYK devices, the driver expects to see RGB colors and > > will do its own internal conversion. > > > > The kinds of deep blue and green highlights which are visible on screen > > are often hard to reproduce with CMYK. This is called gamut compression, > > where the dynamic range of RGB is higher than CMYK. > > > > Welcome to the sometimes murky world of color management. > > > > Now the other side of this is when Scribus has good profiles to work > > with, the color matching is remarkably good. I created some PDF's of the > > Scribus logo with lcms 1.11 and the screen to print is as close as I > > would get from Indesign 2. So yes, the color management does work > > properly. > > > > Feel free to send me files for testing/comments. > > > > Regards, > > Peter > > > > > > > ---------------------------------------------------------------------------- > ---- > > > _______________________________________________ > Scribus mailing list > Scribus at nashi.altmuehlnet.de > http://nashi.altmuehlnet.de/mailman/listinfo/scribus > >
