Scribus

FROM scribus.net If you think free means lacking in professional features, Scribus is the app to change your mind. This open-source desktop publishing tool has colour separations, CMYK and spot colours support, ICC colour profiles, and lots of control over PDF generation.

Import modules to allow you to pull in documents from other tools are aplenty, and a thriving community means updates are frequent. The app has support for OpenType, TrueType and PostScript Level 3 fonts, and well over 100 colour palettes, many donated by commercial organisations and including several government and scientific standards.