An image forming apparatus comprising: a color image forming portion (Pa, Pb, Pc, Pd, 150) for forming a color toner image, and a transparent image forming portion (Pe, 151) for forming a transparent toner image superposedly on the color toner image formed by said color image forming portion (Pa, Pb, Pc, Pd, 150); characterized by comprising a color data obtaining portion (152, 116, 900, 200) to which information corresponding to an original image which is designated by an operator and which is to be used for forming the color toner image in an operation in a test mode is inputted, a transparent data obtaining portion (153, 100, 300, 200, 116) for obtaining information corresponding to an area in which the transparent toner image is superposedly formed on the color toner image corresponding to the original image, an input portion to which an execution instruction of the operation in the test mode is inputted; and a controlling portion for executing the operation in the test mode in response to input of the execution instruction to the input portion, wherein said controlling portion controls said color image forming portion (Pa, Pb, Pc, Pd, 150) and said transparent image forming portion (Pe, 151) so as to form a plurality of test image including a first test image and a second test image in the execution of the operation in the test mode, wherein said first test image is an image obtained by superposing the transparent toner image, formed in a first amount of transparent toner per unit area by said transparent image forming portion (Pe, 151) in the area indicated by the information obtained by said transparent data obtaining portion (153, 100, 300, 200, 116), on the color toner image which is an image corresponding to the original image indicated by information inputted to said color data obtaining portion and which is formed by said color image forming portion (Pa, Pb, Pc, Pd, 150), and wherein said second test image is an image obtained by superposing the transparent toner image, formed in a second amount more than the first amount of transparent toner per unit area by said transparent image forming portion (Pe, 151) in the area indicated by the information obtained by said transparent data obtaining portion (153, 100, 300, 200, 116), on the color toner image which is an image corresponding to the original image indicated by information inputted to said color data obtaining portion and which is formed by said color image forming portion (Pa, Pb, Pc, Pd, 150). a color image forming portion (Pa, Pb, Pc, Pd, 150) for forming a color toner image, and a transparent image forming portion (Pe, 151) for forming a transparent toner image superposedly on the color toner image formed by said color image forming portion (Pa, Pb, Pc, Pd, 150); characterized by comprising a color data obtaining portion (152, 116, 900, 200) to which information corresponding to an original image which is designated by an operator and which is to be used for forming the color toner image in an operation in a test mode is inputted, a transparent data obtaining portion (153, 100, 300, 200, 116) for obtaining information corresponding to an area in which the transparent toner image is superposedly formed on the color toner image corresponding to the original image, an input portion to which an execution instruction of the operation in the test mode is inputted; and a controlling portion for executing the operation in the test mode in response to input of the execution instruction to the input portion, wherein said controlling portion controls said color image forming portion (Pa, Pb, Pc, Pd, 150) and said transparent image forming portion (Pe, 151) so as to form a plurality of test image including a first test image and a second test image in the execution of the operation in the test mode, wherein said first test image is an image obtained by superposing the transparent toner image, formed in a first amount of transparent toner per unit area by said transparent image forming portion (Pe, 151) in the area indicated by the information obtained by said transparent data obtaining portion (153, 100, 300, 200, 116), on the color toner image which is an image corresponding to the original image indicated by information inputted to said color data obtaining portion and which is formed by said color image forming portion (Pa, Pb, Pc, Pd, 150), and wherein said second test image is an image obtained by superposing the transparent toner image, formed in a second amount more than the first amount of transparent toner per unit area by said transparent image forming portion (Pe, 151) in the area indicated by the information obtained by said transparent data obtaining portion (153, 100, 300, 200, 116), on the color toner image which is an image corresponding to the original image indicated by information inputted to said color data obtaining portion and which is formed by said color image forming portion (Pa, Pb, Pc, Pd, 150).