ImageMagick is a gem of a library, indispensable in my tool box. Here are some of my notes on using this excellent piece of software.
Converting from CMYK to RGB colour space
Several pieces of software, included, have problems handling images with the CMYK colour space. Sun/Oracle Java, for instance, will bail out with this error:
Caused by: javax.imageio.IIOException: Unsupported Image Type at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:977) at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:948) at javax.imageio.ImageIO.read(ImageIO.java:1422) at
Luckily, ImageMagick can easily help you out, just do:
$ convert image.jpg -colorspace rgb image.jpg
ImageMagick can also specific CMYK and RGB profiles for the conversion, but for most cases, were you just want RGB, the above should suffice.
I've created a wee script which does this en masse. It works on large archives (where the BASH expansion will go out of bounds if you use wildcards and/or for loops) and file names containing white space characters.
$ convert-images-from-cmyk-to-rgb-colour-space Press ENTER to convert all images in the current directory and all sub directories to standard RGB colour space if they're currently CMYK. To abort, press Ctrl + c now. ./WCC1.jpg is using the CMYK colour space, converting it to RGB ... ./fds1.jpg is using the CMYK colour space, converting it to RGB ... ./ABNIVSEN2.jpg is using the CMYK colour space, converting it to RGB ... ./MM1.jpg is using the CMYK colour space, converting it to RGB ...
And yes, the 'u' in colour is intended :-)