The photo emulsion method of screen printing is perhaps the most exciting method created. It makes fine line drawings, computer-generated images, various hand and commercial lettering, and photographic half-tone positives. The photo emulsion method requires: 1) a screen prepared with the photo emulsion/sensitizer mixture; 2) a film positive or a printed transparency film; 3) a light source that will transfer the opaque images on your positive to the light sensitive printing screen. Diazo Photo Emulsion must be mixed with sensitizer. Three-year shelf life unmixed.