An improved photographic Pt printing process has been developed, which is called the print-out process (POP). No developer is required in this process and the deposition efficiency was significantly improved by more than 6 times on carbon paper (CP) and 22 times on carbon-black-coated carbon paper (CB/CP) over the previously reported develop-out process (DOP) [1]. The Pt particle size can be easily controlled by varying the moisture content in the substrate and was reduced to 5 nm on blank CP by adding a stabilizing agent, ethylene glycol (EG), to the photo-emulsion. Due to the hydrophobic nature of CB/CP, both Nation ionomer solution and ethylene glycol (EG) were mixed with the emulsion during the printing. SEM revealed that on this substrate Pt was distributed as similar to 25 nm clusters consisting of 5 nm particles on the carbon-black. The mass specific catalytic activity for methanol oxidation of Pt printed on CB/CP by POP was increased five times compared to that of Pt printed by the previous DOP. The performance of the POP Pt in a H-2 PEM single fuel cell (5 cm(2)) was also evaluated. A peak power density of 288 mW cm(-2) was achieved with an anode POP Pt catalyst loading of 0.16 mg cm(-2) at 70 degrees C and 0.9 mg cm(-2) JM Pt at the cathode. Compared to the DOP Pt catalyst at about the same loading, peak power density was improved more than four times by using the POP Pt. (C) 2007 Elsevier B.V. All rights reserved.