Basic Screen Printing Process
01. Creating A Design
02. Printing A Design
03. Choosing A Type Of Screen
04. Degreasing A Screen
05. Applying Emulsion
06. Screen Registration
07. Exposing A Screen
08. Washing Out A Screen
09. Taping A Screen
10. Printing
11. Curing
12. Cleanup
05. Applying Emulsion:
* Be sure that you are doing all parts in a light safe environment with a yellow light safe bulb and NO outside or bright light what so ever. This includes mixing your emulsion, coating your screens, drying your screens, exposing your screen, and washing out your screen.
When coating your screen, you want to be sure that your room is very light controlled. Your emulsion is sensitive to bright light, so if you are trying to washout your screen outside or in a brightly lit room, you are running a very high risk that your image will not turn out. Please keep this in mind during this process. A dim yellow “light safe” light is just enough so you can see what you are doing. Do not use any bright fluorescent or halogen lights, as this will ruin your screen.
Depending on the type of emulsion you are using the coating instructions can vary. I’m going to explain how to coat a screen using CCI DXP Diazo-Photopolymer Dual Cure Direct Emulsion. Every emulsion will come with its own mixing and application instructions. You will want to read these instructions thoroughly so you can make any adjustments if need be. The DXP emulsion comes un-sensitized and needs to be mixed with an activator. After the emulsion has been mixed with the activator, the emulsion becomes sensitized and everything must be done in a light safe environment until after the screen is washed out.
To coat your screen I would suggest using an emulsion scoop coater. In your dark room, pour a good amount of sensitized emulsion into your scoop coater. Don’t be afraid to be generous because any unused emulsion can be poured back. Let the emulsion settle for about a minute and then apply one coat of emulsion to the outside or shirt side of your screen. Hold the scoop coater with both hands, one hand at each end and start at the bottom of the screen. Place the sharper edge against the screen and tilt it till the emulsion starts pooling on the screen. Then move the scoop coater towards the top of the screen, all the while applying pressure to evenly coat the screen, you’ll want to hear a zippy sound. If you don’t hear that zippy sound, you probably aren’t applying enough pressure. Once you reach the top of your screen, tilt your screen coater back to catch the excess emulsion. A screen coating stand will help hold your screen in place allowing you to use a good amount of pressure, making coating your screen with emulsion very easy to do.
Once the outside of the screen is coated, turn the screen over and repeat the process on the inside of the screen. To properly dry your screen, place two pieces of wood on the floor and set your screen onto them with the shirt side facing down. You want all your emulsion to settle on the outside or shirt side of your screen, this creates a gasket for printing. As soon as your screen is coated, place a fan on your screen to help dry it faster. Turn the lights off in the room to make the room completely dark. With a fan on your screen, the emulsion should dry in about 3-6 hours. Without a fan, let it dry at least overnight. When the emulsion dries, it should turn a darker color then you originally started with. Another way to tell your emulsion is dry is when it is no longer tacky.
You can pour the remaining emulsion back into the container and close the lid tightly. To clean my emulsion scoop coater, I just use spray it down with hot water right after and the emulsion comes right out.