blurred CMYK JPEGs when using color management
Posted: 2011-04-14T07:08:38-07:00
Hello all,
I observe some unwanted blurring when I convert an image from RGB JPEG to CMYK JPEG.
This can be seen in screenshot taken from Photoshop, input upper left,
output lower left:
If I leave out color management or if I convert from one RGB profile
to another or if the image input is smaller all runs fine.
It doesn't make a difference whether I use QuantumDepth 16 or 32
of if I use littlecms or littlecms2
This is the script I used for testing:
The input file "sample.jpg" is http://dl.dropbox.com/u/84530/IM/sample.jpg
Can anybody confirm if this is a bug?
Thanks, Axel.
I observe some unwanted blurring when I convert an image from RGB JPEG to CMYK JPEG.
This can be seen in screenshot taken from Photoshop, input upper left,
output lower left:
If I leave out color management or if I convert from one RGB profile
to another or if the image input is smaller all runs fine.
It doesn't make a difference whether I use QuantumDepth 16 or 32
of if I use littlecms or littlecms2
Code: Select all
> convert -version
Version: ImageMagick 6.6.9-4 2011-04-14 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC
Features: OpenMP OpenCL
> otool -L `which convert`
/Users/ar/bin/convert:
/tools/ImageMagick-6.6.9-4/lib/libMagickCore.4.dylib (compatibility version 5.0.0, current version 5.1.0)
/tools/ImageMagick-6.6.9-4/lib/libMagickWand.4.dylib (compatibility version 5.0.0, current version 5.1.0)
/tools/ImageMagick-6.6.9-4/lib/liblcms2.2.dylib (compatibility version 3.0.0, current version 3.1.0)
/tools/ImageMagick-6.6.9-4/lib/libtiff.3.dylib (compatibility version 13.0.0, current version 13.4.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1)
/tools/ImageMagick-6.6.9-4/lib/libfreetype.6.dylib (compatibility version 13.0.0, current version 13.2.0)
/tools/ImageMagick-6.6.9-4/lib/libjasper.1.dylib (compatibility version 2.0.0, current version 2.0.0)
/tools/ImageMagick-6.6.9-4/lib/libjpeg.8.dylib (compatibility version 12.0.0, current version 12.0.0)
/tools/ImageMagick-6.6.9-4/lib/libpng15.15.dylib (compatibility version 18.0.0, current version 18.0.0)
/usr/lib/libbz2.1.0.dylib (compatibility version 1.0.0, current version 1.0.5)
/tools/ImageMagick-6.6.9-4/lib/libxml2.2.dylib (compatibility version 10.0.0, current version 10.8.0)
/tools/ImageMagick-6.6.9-4/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.0.0)
/tools/ImageMagick-6.6.9-4/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5)
/System/Library/Frameworks/OpenCL.framework/Versions/A/Libraries/libclparser.dylib (compatibility version 1.0.0, current version 1.0.0)
Code: Select all
IN=sample.jpg
test -r $IN || (echo "not readable: '$IN'"; exit 1)
PROFPATH=/Users/me/iccprofiles
test -d $PROFPATH || (echo "not a dir: '$PROFPATH'"; exit 1)
RGBICC=$PROFPATH/AdobeRGB1998.icc
test -r $RGBICC || (echo "not readable: '$RGBICC'"; exit 1)
RGBICC2=$PROFPATH/eciRGB_v2.icc
test -r $RGBICC2 || (echo "not readable: '$RGBICC2'"; exit 1)
CMYKICC=$PROFPATH/SWOP2006_Coated5v2.icc
test -r $CMYKICC || (echo "not readable: '$CMYKICC'"; exit 1)
OUT1=$IN-no-icc.jpg
OUT2=$IN-cmyk-icc.jpg
OUT3=$IN-rgb-icc.jpg
rm -f $OUT1 $OUT2 $OUT3
# not using any color management
/tools/ImageMagick-6.6.9-4/bin/convert jpg:$IN -quality 100 -depth 8 $OUT1
# using ICC profiles to match from RGB to CMYK
/tools/ImageMagick-6.6.9-4/bin/convert jpg:$IN -quality 100 \
-profile $RGBICC -profile $CMYKICC -depth 8 $OUT2
# using ICC profiles to match from one RGB to another RGB
/tools/ImageMagick-6.6.9-4/bin/convert jpg:$IN -quality 100 \
-profile $RGBICC -profile $RGBICC2 -depth 8 $OUT3
file $OUT1 $OUT2 $OUT3
Can anybody confirm if this is a bug?
Thanks, Axel.
.