“This is How We Do It” (Screen printing 101)
I taught myself how to screen print by watching a few videos on YouTube and buying a kit for ~$40, and so can you! Screen printing is an incredible project to do with kids of all ages: It’s inexpensive, low-risk and hugely satisfying. It certainly belongs in “maker-centered” classes, but it makes sense in straight up AP English classes, too. Here’s how it works:
Screen printing, also known as “silk screening,” is the process of pressing ink through a fine mesh screen. Depending on your design (see below), the screen will allow ink to pass through in certain areas, and will block it in others. You can screen print on lots of different materials, but the most common are fabric and paper. If you own a t-shirt with a design on it, it’s probably been screen printed. Although most screen printing is done with machines, you can use a kit to do the whole process by hand using a squeegee to press the ink through the screen. There are several different methods for creating custom screen designs, and I’ve used these two:
The stencil method:
When you buy a screen as part of a kit or individually, it will be clean: If you hold it up to the light, you’ll be able to see through it completely, even if a bit fuzzily. If you were to print with this screen, the ink would pass through the mesh in a huge blob. So, you need to block the ink from passing through the screen in strategic areas, and one method of doing that is to prepare a stencil. The stencil is taped to the underside (touching the material you’re printing on) of the screen, and you can press ink through it. A stencil can be cut from a piece of plastic “transparency” film with an X-Acto blade (if you want to reuse it) or just a piece of cardstock (if you don’t). Here’s a 2-minute video that illustrates this process.
Stencil is a great method if you want a lot of different customized prints. It’s easy, and kids of (almost) all ages can cut them. Stencil printing can be slightly imprecise because it’s possible for a gap to form between the screen and the stencil, allowing ink to bleed a little bit beyond the boundary of the design. A major disadvantage to this method is that certain shapes cannot be “stenciled.” A heart silhouette, yes; a happy face, no – because once the circular outline of the face is cut out, the inside eyes and mouth “fall out” as well. A better description of this problem (“islands and bridges”) is right here.
The photo emulsion method:
A more precise, but time-intensive, method involves “burning” an image right onto the screen itself. Begin by taking a clean screen and coating it in a material called photo emulsion, which has the consistency of honey. After it dries (I leave it for 24 hours but if you’re in a hurry, use a fan or hair dryer), you won’t be able to see through the screen anymore: ink won’t be able to pass through at all. So how do you “burn” a hole through it to allow ink to pass? Create a design, digitally or hand-drawn, and photocopy it onto a transparency film. Place that film on top of the screen you’ve prepared, and shine a bright light (250 watt bulb) on it for ~45 minutes. Immediately wash the screen out in the sink or shower, and you’ll see the photo emulsion wash away completely in the places where you want ink to pass through your screen. It’s not magic: The light exposes the photo emulsion, hardening it into the screen everywhere except for under the dark ink of the transparency, which was protected from the light. Here’s a video that illustrates this process.
This method is much more precise than stenciling, and it makes many more design options available. (Happy faces are fine here.) However, it’s much more time intensive, the process can fail if any variable (thickness of emulsion, length of time under light, bulb wattage, distance between bulb and screen) is off. You can wash out the photo emulsion with chemicals “reclaim” the screen, but I’ve found that once I prepare a screen this way, I rarely go to the trouble of reclaiming it.
Materials + specifics:
There are other variables to consider after you get going: There are two different types of inks to choose from – water-based and oil-based (also known as plastisol) – and water-based is really the only option that I think makes sense in schools. (I only made that mistake once.) Ink has to be heat-set into fabric or else it will partially wash out; I do this in the classroom by ironing directly on the ink for 2-3 minutes after it’s dry or tell the kids to do it at home. I often string a clothesline up for shirts that are drying. (Ink dries to the touch in <30 minutes.) Hair dryers can help. The mesh count in the screen matters if you’re trying to do a super precise print (for which higher counts, like 220, are better), though I think most “kit” screens are 110. Also, use painter’s tape to block off any areas of the screen that aren’t covered by photo emulsion or stencil but where you don’t want ink to come through.
- Speedball kit (link) – Includes photo emulsion, ink, a screen, squeegee, and drawing fluid (another printing method I haven’t really used). You can also find a stencil version of this kit, but that just includes transparency film and a blade instead of photo emulsion and I don’t think it’s worth it. This is the kit I started with. Most of my ink is Speedball fabric ink.
- Jacquard kit (link) – This one includes the same as above, minus drawing fluid. I just discovered this set and really like the ink; it’s thick and opaque, which means you can print, say, white ink on a black shirt. (Usually inks don’t print well on dark colors.) I haven’t experimented with this photo emulsion.
Finally, it’s helpful to expect that many of your first prints will be kind of bad. Too much ink, not enough ink, etc. Some of mine still are, and I’ve practiced a lot in the past four years. This is totally normal. Kids generally don’t have the same issues with perfection as older folks do.
PS – project ideas:
Check out our post in our Toolbox for a bunch of ideas about how you might use screen printing in your own classroom: https://unprofessionaldevelopment.org/portfolio/screen-printing/
PPS – workshops:
I occasionally teach screen printing workshops out of our space at Girls Garage in Berkeley, CA. Check to see if we have one coming up: http://girlsgarage.org/programs/workshops/