Speedball Art Products 4559 Diazo Photo Emulsion Kit Photo emulsion is best for creating detailed or photographic type stencils for screen printing. Speedballs Diazo Photo Emulsion is a 2-step process where the photo emulsion needs to be activated. To activate, the photo emulsion, sensitizer needs to be added. The sensitizer is a very thick oil and needs water to create the right consistency for adding it to the photo emulsion. (The sensitizer bottle will feel unfilled, but dont worry it is not empty!) No need for a light safe environment or darkroom! Mix photo emulsion under normal light conditions. Set contains 1 each of the following: 6.6oz (195ml) Diazo Photo Emulsion; 2.12g Diazo Sensitizer; 8oz (237ml) Diazo Photo Emulsion Remover and Instructions. Conforms to ASTM D-4236.