An image processing system includes a host computer which generates print data and a printer which prints an image based on the print data. The host computer sets attribute information which indicates a part of the print data which is allowed to be visualized and a part of the print data which is prohibited to be visualized. In addition, the host computer also sets authentication information required for reading the part prohibited to be visualized, and transmits the print data, the attribute information, and the authentication information to the printer. The printer prints a visual image of the part allowed to be visualized on a paper medium provided with an RFID chip and stores the part prohibited to be visualized in the RFID chip. In addition, the printer prints the information stored in the RFID chip on another paper medium as a visual image after authentication with the authentication information.