Section C – Step-by-Step Instructions for Screen Printing
using the teeshirtprinters.com single color press

Step Two – burn a screen

Place your Styrofoam blocks on the work surface in a low-light room. Turn the screen upside down, that is, place it squeegee side down, over the foam. You want to support the entire screen by just the inside, by the mesh. You now need to place the film positive over the emulsion, upside down. By upside down, I mean that when you put the film over the screen, and then look at the work side (up side) of the screen, the design is reversed. Another way to think of it is, that if you were looking at the film from the styrofoam’s point of view, it would read correctly.
Place the sheet of glass over the film and screen to hold everything together tightly. Now, you need to expose it using that halogen work light. You need to expose it with the light 18 to 24” above the screen for ten minutes. If you want to hold it, that will work, or you can rig up a stand – just be sure there are no shadows from the stand interfering with the light hitting the emulsion!

After ten minutes, turn off the light and remove the screen. Put it inside two black plastic trash bags, and head to the car wash. Feed it your two dollars, and with the gentle spray that comes out when you are not squeezing the handle, dampen the entire screen, both sides, while it is still in the trash bags (both sunlight and the security lights in car washes put out a lot of UV light and will expose your screen very quickly until after you wet the screen on both sides!).

Now, you should see a color change – the areas that the emulsion received no light will be getting a milky color and may even start to wrinkle up. When you see this, the printing areas have softened and can be blown out using the high pressure spray. Remove the screen and discard the trash bags. Prop the screen against the wall of the car wash, hold it with your foot, and squeeze the trigger. Cover all the mesh area evenly, and wash the stencil out from the work side. Just go over the screen until it is obvious that all the print areas are washed out.

Once the screen has dried it is ready to print with.

NOTES
· Humidity has a dramatic effect on exposure times when using diazo emulsion, a noticed effect on dual cure emulsion, and just a slight effect on photopolymer emulsions. Since you’re using diazo to practice with, if it is a very humid day, increase the burn time a couple minutes.
· If you want to test your setup to determine the optimum exposure time, look at the end of this tutorial for a diagram and instructions to make a simple exposure test. You can also buy what is known as a ‘step wedge’ and use it to see how long your optimum exposure time is.

Internet Marketing