It has been mentioned about a year ago by Anthony: viewtopic.php?f=1&t=20729#p83381
The main issue is this:
The K-channel shows up, well.. not very black, rater very much like a rainbow.convert rose: -colorspace CMYK -separate +append roses.png
![Smile :)](./images/smilies/icon_smile.gif)
Additionally, I found a difference when previewing the images with x: and show:. The latter seems pretty broken but works fine in RGB. I don't know what the difference is between show: and x:. I made a visual summary:
![Image](http://www.natrox.org/img/magick/rose_separate.png)
pipe@spacelab:~$ convert --version
Version: ImageMagick 6.8.5-5 2013-05-03 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2013 ImageMagick Studio LLC
Features: DPC OpenCL OpenMP
Delegates: bzlib djvu fftw fontconfig freetype jbig jng jp2 jpeg lcms lqr lzma openexr pango png ps rsvg tiff x xml zlib