Abstract: A method of reproducing in an electrostatic copying apparatus a portion of an entire master pattern comprised of toner deposited on an electrostatic latent image onto a reproducing medium. The reproducing medium, itself, is an insulative sheet material which has a copy surface on which the selected portions will be reproduced. At least one first transparent conductive film is deposited on the back side of the copy surface of the sheet material in the area corresponding to the portion of the master pattern which will not be reproduced, and at least one second transparent conductive film is deposited along only one end of the sheet material on the same side of the material as the first conductor film. Finally, a third transparent conductive film connects the first and second films to each other. The method of producing on this reproducing medium begins by feeding one end of the sheet material opposite the end containing the second conductive film into the electrostatic copier.