A Quick Screen Printing Walkthrough (1/2)

Welcome back and today i’m going to do a very basic demonstration on how to screen print. I’m going to show you everything from the design process all the way to exposing and washing out your screen and I'm also going to do a quick design for the purpose of this demonstration. Just a basic one color design on the front of the shirt, nice and small so it should be a very easy print. I also have a bucket of emulsion that’s about to expire because business has been practically non-existent at the moment. Hopefully that changes soon. But let’s go ahead and get started and see how this goes!

All right, I’m throwing together a quick design in Adobe Illustrator. Something that’s small in size and will expose fairly well on a 110 mesh screen because that’s what we’re working with at the moment. Once this design is finished and ready, I will send it to my Canon Pixma IX6820 printer where it will print onto an 8.5” x 11” transparency.

Sometimes I like to print it twice and tape the two transparencies together to make it more opaque. But it really depends on what type of printer you’re working with and how complicated your design is.

Before we can coat our screens with emulsion we need to make sure they’re nice and clean. So I have a used screen that I’m going to reclaim by first stripping the emulsion. I will first get my screens wet and then spray both sides with an emulsion remover and let it sit for about 10 minutes. Just let the remover do its job. After about 10 minutes I’ll simply spray it thoroughly front and back with the pressure washer. I always keep the spray wand at least a foot away from the screen so I don’t do any damage to it. Hold it up to some light and inspect it closely to make sure you got it all off.

Next, it’s important to degrease your screens. It’s a similar process. You spray both sides of the screen with a very small amount of degreaser. A little bit goes a long way. And pro tip, you want to make sure that you use a dedicated scrubber. Meaning that you have a scrubbing brush on hand that’s dedicated only to degreasing screens and nothing else. You don’t want to get other chemicals or anything else on this brush that could contaminate your screens as that could affect your emulsion. And just make sure to thoroughly spray all that degreaser off the screen so that it’s squeaky clean. Then find a place to dry your screens off.

Once it’s nice and dry we’re going to coat it with the emulsion using a scoop coater, in a light safe environment of course. We take our emulsion and carefully pour it into the scoop coater. As with most of this process there’s all kinds of ways that you can do this but I like to hold the screen with one hand and lean it back slightly. I was taught to first coat the outside, or the back of the screen first, then the front. I’m not entirely sure why but it works for me so I just go with it. This part takes practice and your main goal is to coat it as evenly as possible. You want a smooth thin, even layer of emulsion on your screen. So I do one coat on the back and one coat on the front. Then you find a place to let it dry. It has to be a light safe, low humidity environment if possible and getting a dehumidifier helps with this.

Also, drying the screens horizontally as opposed to vertically is also better for reasons I don’t understand. Keep the outside, or back of the screen facing down. You should leave these to dry for at least 12 hours. I like to shoot for a minimum of 24 hours. This is unless you have one of those big expensive drying cabinets. But if you have one of those then you’re probably a legit professional and why the heck are you reading this?

Now it’s time to expose our screen and I’m going to try not to throw numbers and times at you because this might be the most variable part of the whole process. There’s just so many factors to consider. Your exposure unit, your environment, emulsion type, screen type, mesh count, etc. All of this affects how long you need to expose your screen. But the overall process is really the same so you can simply tape your transparency to the back of the screen making sure you have it in the right orientation for printing. You should measure it to make sure it’s nice and centered. Then put it on the exposure unit. I add a bucket on top to apply a little bit of pressure. Then I set my timer and cook the screen.

Once the timer goes off, promptly flip that switch and remove the transparency film. I head back over to the washout booth and get our screens nice and wet–both sides. Remember to continue to keep the lights off at this point because the emulsion is still sensitive to light. I let it soak for a few minutes so the emulsion can absorb some of the water. This does something chemically to stop the exposing process. Also, letting it soak for a few minutes makes it wash out a little easier.

Now you can turn the lights back on, take your pressure washer and carefully wash out your design. I recommend getting an exposure calculator as this could help you dial in your exposure times and troubleshoot any problems you might run into.

Hopefully your design came out perfectly. You can hold it up to some light and do a quick inspection. Then it’s back to the drying rack.

Stay tuned for part 2 where we take our screen and print some shirts!