An exciting method of screen printing, for fine line drawings and photographic half tone prints, giving over 300 prints on polyester or synthetic screen materials.
The Speedball Diazo Photo Emulsion Kit contains 236ml Diazo Photo Emulsion, 1 Diazo Sensitizer, 236ml Photo Emulsion Remover. Full instructions are included.
The resist is prepared by mixing the photo emulsion and sensitizer; the sensitised liquid can be kept for 2 months at room temperature and up to 10 months in a refrigerator. Spread a thin, even coat of the mixed liquids on both sides of the screen. Allow the screen to dry thoroughly away from light and heat. The prepared screen will keep for up to 2 weeks, away from light, until it is ready to be used.
A black, high contrast image on an acetate sheet is the ideal master to place onto the screen mesh. A 150W clear incandescent bulb or photoflood is held 30cm above the screen. The areas of diazo not exposed to light remain soft, while those areas exposed to the light (or sun) harden. Exposure times range from 10-90 mins, depending on the screen size and light source. After exposure the unwanted soft emulsion is removed from the screen with a strong spray of cold water or Photo Emulsion Remover. The hardened, exposed photo emulsion will remain on the screen and become the stencil.
The screen can be reclaimed using the Photo Emulsion Remover included with this kit.