Abstract: In transferring color image data having a tone on a recording paper, a threshold matrix data for adjusting the tone is selected in accordance with the image data having a dot arrangement. The threshold conversion curve of the threshold matrix data selected is used to correct a variation in the tone of the image data due to mechanical and electrical variations in a color image transferring apparatus including variations in the rotation speed of a transferring drum, a power source voltage to be applied to a transferring head and a relative position between the transferring drum and the recording paper. This correction can achieve improved transference of the image data on the recording paper.