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falsification of colors at changing profiles (rgb-cmyk)

Posted: 2008-01-15T16:01:34-07:00
by peegee
Hello,

At first, sorry for my bad english but I am not a native english speaker.

I use Imagemagick in many situations in my website.
But now I have a very extraordinary problem.

In this situation i use Imagemagick to change images from rgb into cmyk. Therefore i use two profiles.
Code looks like this:

Code: Select all

$rim="convert -profile AdobeRGB1998.icc -profile FOGRA27.icc rgb.jpg cmyk.jpg";
exec($rim);
basically these lines work on my pc.
but on the server there a slight difference. for example, white areas get a slight coloration. (1% cyan, 1% yellow). This is very annoying at printing the images.

I have no idea, where this difference comes from.
I speculate that this problem comes from the different Imagemagick-versions which are installed on my pc and on the server.

It does not work on the server with:
ImageMagick 6.3.1 12/18/06 Q16

It works on localhost with
ImageMagick 6.2.9 08/28/06 Q16

and also at another server with
ImageMagick 6.2.4 12/13/06 Q16

Are there any other reasons where this problem could come from? Default settings?

Please, help me to solve this problem. It is very importent for me.
Thanks a lot,
peegee

Re: falsification of colors at changing profiles (rgb-cmyk)

Posted: 2008-01-15T17:53:06-07:00
by magick
The current ImageMagick version is 6.3.9-10. To account for any differences, first verify if your version of ImageMagick includes LCMS support. Type
  • identify -list configure
LCMS should be associated with the DELEGATES and/or the LIBS tag. If the LCMS delegate library is not available, ImageMagick uses an internal less accurate algorithm to convert from RGB to CMYK. It also possible to get slightly different results if you are using different versions of the LCMS delegate library.

Re: falsification of colors at changing profiles (rgb-cmyk)

Posted: 2008-01-16T00:40:52-07:00
by peegee
thanks for your answer.

I am not sure, if LCMS library is available.

This is the content of the configure-file on my pc:

Code: Select all

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuremap [
  <!ELEMENT configuremap (configure+)>
  <!ELEMENT configure (#PCDATA)>
  <!ATTLIST configure name CDATA #REQUIRED>
  <!ATTLIST configure value CDATA #REQUIRED>
]>
<configuremap>
  <configure name="NAME" value="ImageMagick" />
  <configure name="LIB_VERSION" value="0x629" />
  <configure name="LIB_VERSION_NUMBER" value="6,2,9,3" />
  <configure name="RELEASE_DATE" value="09/15/06" />
  <configure name="VERSION" value="6.2.9" />
  <configure name="HOST" value="Windows" />
  <configure name="COPYRIGHT" value="Copyright (C) 1999-2006 ImageMagick Studio LLC" />
  <configure name="WEBSITE" value="http://www.imagemagick.org" />
</configuremap>
This is the content of the configure-file on the server:

Code: Select all

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuremap [
  <!ELEMENT configuremap (configure+)>
  <!ELEMENT configure (#PCDATA)>
  <!ATTLIST configure name CDATA #REQUIRED>
  <!ATTLIST configure value CDATA #REQUIRED>
]>
<configuremap>
  <configure name="NAME" value="ImageMagick" />
  <configure name="LIB_VERSION" value="0x631" />
  <configure name="LIB_VERSION_NUMBER" value="6,3,1,2" />
  <configure name="RELEASE_DATE" value="12/18/06" />
  <configure name="CONFIGURE" value="./configure /usr/share/config.site /usr/etc/config.site" />
  <configure name="PREFIX" value="/usr" />
  <configure name="EXEC-PREFIX" value="/usr" />
  <configure name="VERSION" value="6.3.1" />
  <configure name="CC" value="gcc" />
  <configure name="CFLAGS" value="-O2 -march=i486 -mcpu=i686 -Wall -W -pthread" />
  <configure name="CPPFLAGS" value="-I/usr/include" />
  <configure name="PCFLAGS" value="" />
  <configure name="DEFS" value="-DHAVE_CONFIG_H" />
  <configure name="LDFLAGS" value="-L/usr/lib -L/usr/X11R6/lib -lfreetype -L/usr/lib" />
  <configure name="LIBS" value="-lMagick -llcms -ltiff -lfreetype -ljpeg -lXext -lSM -lICE -lX11 -lXt -lbz2 -lz -lpthread -lm -lpthread" />
  <configure name="CXX" value="g++" />
  <configure name="CXXFLAGS" value="-O2 -march=i486 -mcpu=i686 -Wall -W -pthread" />
  <configure name="DISTCHECK_CONFIG_FLAGS" value="'CFLAGS=-O2 -march=i486 -mcpu=i686' 'CPPFLAGS=-I/usr/include/freetype2 -I/usr/include/lcms '  --with-quantum-depth=16  --with-$
  <configure name="HOST" value="i686-pc-linux-gnu" />
  <configure name="COPYRIGHT" value="Copyright (C) 1999-2005 ImageMagick Studio LLC" />
  <configure name="WEBSITE" value="http://www.imagemagick.org" />
  <configure name="QuantumDepth" value="16" />
</configuremap>
looking at these lines it should work on the server but not at my pc. but it is inverse.
or is there also a mistake at the code from the server?

thanks for your help,
peegee

Re: falsification of colors at changing profiles (rgb-cmyk)

Posted: 2008-01-16T08:37:00-07:00
by magick
You have LCMS support in both your instances of ImageMagick. If you have the time, try upgrading to the latest versions of ImageMagick on your PC and the lastest ImageMagick and LCMS library on your Linux server. If you still get differences in results, post a sample image and the command you use and we will investigate and either fix the problem or account for the differences.

Re: falsification of colors at changing profiles (rgb-cmyk)

Posted: 2008-01-16T14:15:46-07:00
by peegee
i changed image magick and the lcms library on the server to the latest versions and now it works.
thanks for your help.
you are great!