Screenprinting is a difficult, multi-stepped process that provides plenty of challenges even for the most experienced printer. Troubleshooting is the most frustrating aspect to printing. Thousands of seemingly inconsequential things could go wrong early on, leading to big, time-consuming mistakes further down the road. However, there is a certain order to the process and learning the basic steps is fairly simple. Here they are - but remember, even the simplest thing to screenprint, one-sided, one-colored light shirts - can prove very difficult to master:
1) First, the screenprinter chooses which artwork will go on the shirt. Simple, bold art works best, with easily readable text. Fine lines or dot screens often do not print easily. If the artwork is the wrong size, a large camera is used to shoot the artwork onto another piece of paper, using multiple lenses to change the size, keeping the proportions intact.
2) The same camera is used again, this time to shoot the artwork onto a clear acetate sheet. The acetate is then placed onto a screen, which is a large frame filled with a thin mesh. The screen has already been coated with a light-sensitive chemical, and kept in the dark. The screen, with the artwork attached, is placed on a high-intensity light table which floods the screen with light. This hardens the chemical, except where the light doesn't hit - the black lines of the artwork.
3) A hose is used to spray the excess chemical off of the screen. The hardened chemical stays, while the non-lit chemical is washed away, leaving the image behind. The screen is then dried with a blow dryer. Any mistakes or pieces of chemical accidentally shot out are touched up with a special paint. This leaves untouched mesh only where the lines of the artwork are - when ink is pressed into it, it only goes through these spots.
4) The screen is then taken to the screen printing machine - a round, waist high table with from two to six rotating stations. The screen is fit into one of these stations, lined up with a ruler to match the base, and tightened into place. A shirt is placed onto the base and lined up so the image appears where it is intended.
5) Then a color ink is picked and placed into the screen. Unlike regular paint, the ink is thick and sticky, and a very small amount is needed. A piece of bendable plastic attached to a handle, called a squeegee, is dragged across the screen once to spread the ink over the image and again, harder, to push the ink through. At this point, several tests are done on scrap fabric to make sure everything is running smoothly.
6) Now the shirts are ready to be printed. A shirt is placed on the base, lined up, and then printed by pulling the squeegee across the screen. Finished shirts are placed on a conveyor belt through a dryer, heating the shirts to hundreds of degrees and permanently setting the ink.
7) All that is left is to grab the hot shirts at the end of the conveyor belt and fold them neatly. Hopefully, the shirts are all looking good and another successful printing job is finished. Unfortunately, there's one last step: the clean-up process, which is almost as complicated as printing, and not as much fun.