When rendering or optimizing images with a CMYK color space (DeviceCMYK), Qoppa’s PDF libraries and components need the cmykProfile.jar to be present in the classpath. If you forget to include this jar, you will get images with “weird” colors.
Faces for instance will show with more intense, bright saturated colors (such as red and blue) that are darker, more contrasted. See for instance below.
Images when cmykProfiles.jar is present in classpath:
Images when cmykProfiles.jar is missing in classpath: