A method and apparatus for printing a security mark via a non-fluorescent toner is disclosed. For example, the method may be executed by a processor and includes receiving an electronic file of a security mark to be printed on a substrate, determining an amount of halftone coverage for a non-fluorescent toner based on a brightness of the substrate, converting the electronic file of the security mark into a printer description language with the amount of halftone coverage that is determined, and causing the security mark to be printed on the substrate.