Brush photo emulsion on the top/outer side of the screen, so that a thin layer covers the entire screen surface. Do not cover the image to be printed, however. This will need to remain open to allow ink to pass through and create the image on your t-shirt or paper. Allow the emulsion to dry. Keep the emulsified screen in the darkroom so that it does not get prematurely exposed.
Print out the image you are using from your computer to vellum, preferably with a laser jet printer. Attach the vellum to the top/outer side of the screen so that it touches the emulsion. Lay the screen out flat on a table and shine light onto it with a BBA No. 1 Photoflood bulb or a 150-watt incandescent bulb. Exposure times vary depending on the size of the screen. One to two hours of exposure time is a good estimate.
Use some sort of forced water sprayer, such as a pressure washer to blast the emulsion in the screen before removing the screen from the darkroom. The open, exposed areas of your image will wash away, leaving behind the unexposed areas, creating a negative that can be used to print the image.
Tape the inner edges of your screen with masking tape. Divide the tape so that half of it attaches to the inner screen frame and the other half attaches to the screen itself. Run the tape all the way along the inner edges on each side of the screen in order to prevent ink from being pushed out of the image are by the squeegee when printed. Hold the screen up to a light. Locate and cover any registration marks or pinholes with more masking tape so that they will not print.
Attach your screen to a table and piece of wood that is width of the screen, using hinges and and bolts. The piece of wood should also be the same thickness of the screen frame so that the screen will lay down flat on the table. Screw the bolts into the screen and the wood. The screen should be able to pivot at least 45 degrees, but not more than that. More pivot and could allow the ink could get in unwanted areas. A stick can also be attached to the table so that it props the screen up at a 45-degree angle when not in use.
Use a palette knife to remove ink from its bucket. Spread a line of ink on the bottom of the screen, below the image. Place your surface to be printed beneath the screen. Paper can easily be placed flat on a table, but to print t-shirts, special platens that separate the fronts and backs of shirts must be used.
Flood your screen with ink by pushing the screen forward, so that the handle is angled away from you. Push ink along the entire print to cover the whole area. Now pull the squeegee back, with the handle facing you. Press down hard to get a good impression. Lift the screen to reveal your print.