Speedball DIAZO Photo Emulsion. The photo emulsion method of screen printing allows artists to create fine line drawings, computer generated images, hand and commercial lettering and photographic half-tone positives without the need for a darkroom or costly equipment.Offers unlimited creative potential and excellent results. Photo emulsion may be used with any water-soluble or solvent-based ink, but is only compatible with polyester screen fabrics. Must be mixed with Speedball DIAZO Sensitizer. 3-year shelf life, unmixed. Removed easily from screen with DIAZO Photo Emulsion Remover.