Step 3: Exposing your digital image on the coated screen
Great, now take a look at your screen. You might find tiny specs of dust/dirt that dried up with the emulsion, don’t worry about it, you’ll get better at it. If you’re screen is buttery smooth, good job- you’re halfway to becoming a pro-coater! Now it’s time for some exposing.
What you need:
Digitally printed image
A piece of glass
Spray mount or any type of sticky tape, I use clear tape.
A piece of black cloth and cardboard
While still in the dark room, stack up accordingly. From the bottom, up.
1. Black piece of cardboard (same size as your screen) to soak up the UV rays during exposure
2. Screen with squeegee side facing upwards
3. Digitally printed image
4. Glass panel or clear tape to hold down the transparency to the screen. The pros use spray mount (sticky spray).
clear tape to make sure the image stays put
Okay, great. Now take a deep breath and calm down. Before you leave the darkroom, do this:
1. Set your Stopwatch to 00:00
2. Make sure you cover up your project (I use a big black cloth) until you get out into the Sun – otherwise random UV rays will mess up your emulsion.
3. Fill up a tub/basin/bath with warm water to soak your screen in after.
Okay, once your done, take your project outside. Remove the cloth/cardboard, and start the countdown.
Here’s where the magic takes place. The emulsion is a light sensitive chemical in which will harden up when UV rays are present. During exposure your blacker than black image keeps the light from hitting the emulsion. So later on, when you take your screen to wash, the area that hasn’t been exposed will wash off – leaving you a stencil of your digital image. Beautiful isn’t it? Now you know why you had to get the perfect digitally printed image!
Note: Some emulsions will change color when exposed to light (mine turns from pink to a dark purple). Some are green, some are yellow.
In order to determine exposure time, you can consult with the people who sold you the emulsion, or check its label – most would include recommended exposure times. But if you’re like me who got it wrong the first 3 times, then do this. Draw a table/chart with the amount of coating versus the exposure time to find out the balance.
Remember, the amount of emulsion coats you have will correlate with the amount of time you need to properly expose your image. When I made my chart, I had set my exposure times to 15 seconds, 30 seconds, 45sec, and 60 seconds under the sun. It didn’t take me long to figure out an optimum.