To create the stencil on the screen, you need photo emulsion and the image you want printed on a clear transparency sheet. The image can be printed onto the sheet from a computer or simply drawn on with dark ink. Pour the emulsion onto the screen. Lay the transparency sheet onto the emulsion-covered screen and then expose the emulsion to bright light. The light will dry and harden the emulsion except where it is covered by the dark image. This can take up to a full day, unless you have a device that uses ultraviolet light. Once the exposure time is complete, remove the transparency from the screen and then run water on the screen, washing away the emulsion that didn't harden and leaving you with your emulsion-based stencil. To remove the emulsion after use, pour an even mixture of bleach and water onto the screen and scrub it with a bristled brush.
Lay the object you're printing on to flat on a surface; if it's a shirt, make sure it's smooth and ironed. Insert a piece of cardboard, posterboard or other blocker inside the shirt to prevent ink from bleeding into the back. Place the screen flat on the object, centering it for the place you want the image printed. Pour the printing ink onto the screen; pouring it near the top of the screen works best. Using the printing block, sweep the ink across the screen, making sure the ink presses onto the object below where the stencil is. Once you run the ink completely over the stencil, remove the screen and wait for the ink to dry.