It was previously reported that a small amount of metallic zinc was electrolytically deposited on the photoconductive zinc oxide resin laver which was imagewisely exposed to light. Deposited zinc image was developed with 2, 3, 5-triphenyltetrazolium chloride (TTC) or phosphomolybdic acid (PMo) to produce 1, 3, 5-Triphenylformazan Red (TF) dye or Molybdenum Blue (MoBlue), respectively. We have investigated the quantum efficiency and the covering power of zinc or TF in the developing process. The quantum efficiency of electrodeposited zinc was up to 60. The conversion efficiency of electrodeposited zinc to TF was 75% at 3.3×10^-1mol/l TTC-methanol solution. The covering power of TF was about 10 times greater than the deposited zinc, and it was consistent with the covering power derived from the absorption coefficient of TF in methanol.