DIY Screenprinting - Part 2

We're back with the second half of our DIY screenprinting how-to. Yesterday, we built a light exposure unit on the cheap, and we are now ready to get our final art transferred to the screen and ready to print.


Part 2 : Exposing The Screen

Before starting this step, there are a few items that you will need to have. I picked up everything on this list from Pat Catan's, but you can also get them at Michael's or even on Amazon.com.

Here is the list of items that will be needed (the links go to amazon.com for photo reference):

- 10" x 14" Speedball Screen Printing Frame
- 10" Squeegee (for spreading both the emulsion and then the ink)
- Speedball Diazo Photo Emulsion Kit (contains a bottle of photo emulsion, a smaller bottle of developer and a bottle of emulsion remover)
- A clean piece of glass or plexiglass that is larger than the screen (I used a piece of replacement glass for a picture frame)
- A piece of inkjet-compatible transparency

To begin part 2, we must have artwork ready to use. For this how-to, I used the artwork for our new 2013 yard haunt shirt, based on our new logo. I created this artwork in Adobe Illustrator. I recommend using it or another vector art-based program when setting up your work versus a pixel-based program like Photoshop. The vector art will give you clear and crisp shapes and will produce a better image when printed.

The final artwork was converted to a black and white image (no greytones), where the black will print through and the white will block out. Once the art was finalized, I printed it out on a piece of inkjet-ready transparency. I made sure that I used a "best quality" setting on the printer to insure that I got a rich black on the printout. If you don't have a piece of transparency, you can take your art to a local FedEx Kinko's and have them print one for you.

Once the transparency was printed out, it was time to mix the photo emulsion and apply it to the screen. The Diazo Photo Emulsion was easy to mix (add water to the developer bottle and then mix that into the emulsion - the final mix will turn green) and was very easy to apply, as you did not have to apply it in the dark. I used the squeegee to apply a thin, even coating to both sides of the screen.

(Note that the dark image on the screen in the photo above was a ghost image from the previous project that was applied to this particular screen. The black ink from that previous screen actually stains the screen, but the screen was completely cleaned before the new emulsion was applied.)

Once the even emulsion coating is applied, I let the screen dry completely in the dark. I could be wrong, but I think that once the emulsion dries, it becomes light sensitive, so keep it in very low light until it's time to use the exposure unit...

When the screen is completely dry, it is ready for the image to be burned into it. This is where you take the transparency printout and tape it to the bottom (flat) side of the screen. VERY IMPORTANT: be sure to attach the transparency "backwards." This way, the image will read the right way when you go to apply the ink from the opposite side.

With the transparency taped tightly to the bottom of the screen, place it onto the light exposure unit. Place the oversized glass on top of the transparency. This will form a tight seal on the screen and insure that you get nice, crisp contrast when the screen gets exposed to the light.

Once everything is in place, turn on the halogen lamp on the top of the exposure unit.

I have found that an exposure time of 15 minutes works well with a 500 watt lamp. Simply turn on the light and leave it be. After the 15 minutes is up, turn off the exposure unit lamp. I have a utility tub in my basement that I use to wash the screen after exposing it. I run lukewarm water over the screen at a brisk flow. After a few minutes, the areas that were black on the transparency will wash out, leaving your new image in your screen. Be sure to wash all of the detail areas out, because the ink will only pass through the open areas of your screen.

Gently dab the excess water from the screen with a paper towel, and then let the screen dry completely overnight. In the morning, your new silkscreen will be ready for printing.