Os is probably the most prolific macro writer for CorelDRAW and Corel PHOTO-PAINT. Even those who have communicated with him know very little about him. Yet he keeps putting out some incredibly useful macros, many of them with no cost.
The latest, wOxxOm Curve Channel Mixer, allows you to easily adjust the CMYK values of selected vector artwork. If the art isn’t already in CMYK, it will make the conversion for you. This is great if you are working with clipart images.
The dialog at right gives you an idea of how it works. Note that I’ve downsized it to half size so it will not be as clear as when you are running the macro. Given that the macro is free, you definitely want to download it and give it a try to see how it can help your workflow.