File determination system, file determination method, and information processing device

The present invention provides a document determination system, a document determination method, and an information processing device capable of simply determining whether or not a print is a real print. A file determination system is provided with: a server device that stores file data; a second compound machine that generates a real printed matter in which a file indicated by the file data stored in the server device is printed, and at least a portion of the file is printed by compound black, which is black represented by inks of a plurality of colors; and a third multifunction printer that reads a printed surface of a read object including a real printed matter or a duplicated printed matter obtained by duplicating the real printed matter, the server device being configured to read the printed surface of the read object on the basis of whether or not at least a portion of a file indicated by read data generated by the reading of the third multifunction printer is printed with composite black. Therefore, wh