Exposing screens for screen printing at home is possible, and you can do it even without investing in expensive units. I will share my own practices on how I do this.
First, let's make sure you've got everything you will need for this process:
Your screen (duh)
Your artwork on a transparency or tracing paper
Photo Emulsion + scoop coater
UV Lamp
A room that could be completely dark (I use my hallway as it has no windows) or a big box that you could close and it would not let any light through.
A timer (I use the one on my phone)
Fan \ Hair dryer
Your Shower
The glass (or plexiglass) front of a picture frame - needs to be at least the same size as your screen.
If you're reading this, I could assume you've got your artwork ready. If you haven't done this yet, read my previous post on How to prep your artwork for screen printing, and once you're ready come back here to continue.
Before we start, make sure your screen is dry and not dusty, and that all your tools are clean too.
Step 1 - Coat the screen
Go to a room that is not too bright - avoid direct sunlight. I usually do this in the bathroom, and I cover the lightbulb with a scarf so it is not too bright. Try to get the lighting as low as possible, as long as you can see what you are doing. We do this because the photo emulsion is sensitive to light, and you don't want to ruin your whole bucket by opening it next to a sunny window.
Using a spoon, transfer some of the emulsion to your scoop coater. I normally have it half full, otherwise, it would either be overflowing on the sides or not enough and the coating would be patchy.
The next part is a bit tricky- make sure your screen is secure and not moving. If you are a beginner- have another person hold it for you, so you can use the scoop coater with both hands. I got used to holding the screen with one hand, and coat with the other.
We will be trying to cover as much of the screen area as we can, but covering edge to edge is not possible anyway.
Now, take a deep breath.
We will start coating the printing side.
Your scoop coater is now filled to the middle, place it at the base of your screen. Tilt it slightly so the photo emulsion starts slowly moving towards the mesh. Once you see the emulsion touching the screen, slide the coater upwards, keep it tilted and with even pressure all the way through. Try to do this movement quickly.
I would then do this a second time, but keeping the coater not tilted - so I just scrape off some of the excess emulsion - we do not want our layer to be thick.
Hopefully, you will find yourself with an even layer of emulsion. If you have any dry patches, do this again, and then collect excess with the coater again.
Now, flip your screen with the squeegee side facing towards you. You would need to do this on this side as well.
After that, clean up any drips or excess emulsion again with the coater.
I find this part stressful, so I am always glad when it is over!
Step 2 - Let it dry
You will need to put your screen in a horizontal position in a dark non-dusty place. We do not want any dust particles sticking to the emulsion. If you do not have a room that can go completely dark, put it in a big enough box and close it up.
Now we wait for the screen to dry. I would place a fan to speed up the process.
Before moving on to the next step, we need our screen to be completely dry.
Step 3 - Expose your screen
Now, for the big moment! I would do the coating process the day before I plan on exposing my screen, so I am sure that it is 100% dry.
This process is very tricky because there are many variables - your exposing time depends on your emulsion type, thickness layer, your lamp, and the distance you place your lamp from the screen. Especially if you are using a DIY setup as I do it could be a bit complicated to figure it out, but once you have you can use the formula going forward.
I am working on a separate blog post on how to figure out your timing without having to ruin a million screens- once it is ready I'll come back and link it here.
Let's prepare our exposing setup! You still need to keep your screen in the dark. Your setup needs to be in the dark, be it in a dark room or in a contained area. No light should be reaching your screen, other than the UV lamp.
I would have my screen on the floor, then I place my artwork on top of it, and then a glass sheet I took off from a picture frame. We put the glass on top to keep the artwork flat and in place.
*Make sure you've placed your artwork correctly and not mirrored - when you look at it from the squeegee side, it should be the way you want it.
Then, I use one of those IKEA step chairs as a construction to put my lamp on facing down flat towards the screen (see the photo below). This allows me around 40cm distance from the lamp to the screen. You're going to have to get a little creative with this process and figure out something to use as a lamp stand.
This is what my setup looks like:
Now have your timer set at the amount of time you want to expose your screen. I do it for 7 minutes and 45 seconds, with a 50W UV Led bulb and 40 cm distance, a thin layer of emulsion.
Turn the light on and off with the beginning and the end of your timer.
Now your screen is exposed, you do not need to hide it from the daylight anymore. But we are not done yet!
Step 4 - Wash it off!
Take the screen to the shower. Wet it on both sides with low pressure and lukewarm water. Leave it to rest for 30 seconds up to a minute. Usually, you can start seeing very faintly your artwork starting to appear.
After the screen has had its rest, you can now just full-on wash it using more pressure. The areas where your artwork is originally black should wash off completely and the rest should stay intact.
Troubleshooting common problems:
If the emulsion appears soft and cakey, it might be too thick and therefore underexposed. You could try coating thinner layers, or expose for a longer time.
If your whole screen just washes off, it is most probably just underexposed. Try exposing for a longer time.
Step 5 - Let it Dry (again)
I know at this point you might be sick and tired from waiting for your screen to dry, but... we have to do it AGAIN. After you've washed it, you need to let it dry completely before starting to print. To speed it up, you can use a fan. I use my hairdryer sometimes because it has a cold setting. You can use a cloth to dry the frame, but I would avoid wiping the screen with fabric because small particles could get stuck in the mesh and block it.
Drying this time takes considerably less time than when we had to wait for the photo emulsion to dry, so that's that...
Now that your screen is exposed and dry, you can start printing- this is the fun part!
This is it!
I hope this guide on exposing screens at home was helpful to you! I am really happy to be able to do this at my place, and have the whole printing process under my own control and not rely on outside companies. There is of course going to be a learning curve if you are beginner, and especially if you are teaching yourself on your own. You will most probably ruin some screens and get some faulty products, but keep you practicing and you will advance very quickly and become a pro!
Happy printing!
-Clementine
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