We propose a computational alternative photographic process that integrates computer processing with the conventional printing method, particularly cyanotype. Cyanotype is a non-silver-halide process that has a lower environmental impact and is known for its availability to produce tri-color prints; however, the tri-color process is complex and time-consuming. To simplify this heavy printing process, our framework provides a user interface for image editing and optimization based on color simulation within a printable color gamut. We demonstrate image editing and tri-color cyanotype printing using our framework, indicating that it can reduce the number of user trials and errors.