Wash out the Screen
Lesson 9 from: Intro to Screen PrintingErin Dollar
Wash out the Screen
Lesson 9 from: Intro to Screen PrintingErin Dollar
Lessons
Class Introduction
04:27 2Printing Process in Action
04:28 3Gather Materials & Setup Worktable
13:18 4Create Design with a Transparency
10:07 5Set up your darkroom
05:20 6Degrease your screen
07:26 7Coat the Screen with Emulsion
26:43 8Expose the Screen
09:13Lesson Info
Wash out the Screen
This is where we start to see our image appear on the screen, so we're gonna go ahead. We've got out light off after the exposure time. We expose for nine minutes, which is the maker's instructions on the bottle, based on the lamp that we're using as well as the mesh, there's a lot of variables in exposure time, so you wanna make sure to just follow the manufacturer's instructions on that. So, when we're washing out, we're gonna have the printing face out. That's the side that we're gonna spray with water. You can spray both sides, but we like to start with this side, and essentially, what happens during this process is called development, so the first thing that we're gonna do is we're just gonna lightly coat the screen with water which is gonna develop the image in the screen, and then we'll use a high air pressure spray to blow that soft emulsion that was covered by our imagery out of the screen to create that stencil. This is the fun part. Oh, get close, this is very exciting. (hos...
e spraying) And here, we can start to see our image developing. It's hard to see from far back, but we're gonna wet this side of our screen as well. (hose spraying) Now, we're just gonna let that sit for about a minute while it's developing, and essentially, what's happening here is the photo chemicals are just processing, you can sort of start to see your image coming through here. It's a little bit hard to see. Some things to keep an eye out for: We wanna keep it wet. We can use a gentle stream at this point because the emulsion is still pretty fragile at this point. Some things to keep an eye out for at this stage. If you start to see yellow, sort of, shiny oily substance on the surface of the emulsion, that means that the Diazza wasn't mixed in correctly or that your screen is underexposed, that you didn't expose it for enough time. If you're starting to see that yellow chemical, that's the photo sensitive chemical in the emulsion that's washing out in a wrong proportion, in an incorrect proportion, so we're starting to see this development process happening here. We're really excited, really excited, so we're just gonna continue to keep that wet for another few seconds, and then, we're gonna use the higher pressure to blow out that emulsion that's still soft. Everything else around it is hardened because it was exposed to light. Okay, and we wanna do this, pretty much, as quickly as possible, we don't wanna use a ton of water for this process because the more water you use, the more likely it is that the emulsion's gonna try to separate from the screen, and it's not gonna be a crisp impression. So, I'm gonna go ahead and start spraying this out, and you can instantly see the difference here. These are the areas that were covered by our drawing and are now an empty space that the ink is gonna be able to pass through. (hose spraying) Yeah, you guys it's working! (laughs) And this is a celebratory moment because this part of the process is really really challenging, especially in conditions that are less than ideal, so you can see we are getting a little bit of unevenness here, but that's okay. That's actually, mm, that might be problematic. (hose spraying) Yeah, okay, so we overshot, unfortunately, this was not exposed quite enough, so we're seeing the emulsion tear away. It also may be because we used a little too much water in this process, so essentially, what happens when a screen is underdeveloped is you start to see, either tears in the emulsion here, as it separates from the screen or the image won't be crisp. This is actually probably pretty passable. We can tape these areas off and go ahead and print with it, but what we're starting to see is this bubbling. This emulsion is just peeling away, and so that's a mark of underexposure, so we probably either should have used a little bit more time in the exposure, a little more time under the light, or we could have done a brighter bulb, we could have used a higher wattage bulb, or I think that's probably the only two that would be for this, there's a couple of other possibilities for why this is happening, potentially, the emulsion wasn't mixed totally thoroughly. That's something to keep an eye out at home. If it's not mixed correctly or there's too many bubbles, you're gonna see inconsistencies, either like this or like bubbles, this is really pretty signature of underdevelopment, but luckily, you know, if this happens to you at home, once you've got your imagery and it looks pretty clear and you can see that there's enough image there, you don't need to keep washing it out, just stop here, especially if, like we have here, the screen is actually pretty salvageable. It doesn't look beautiful, but what we could do is we can go ahead and go over here. Go back to our UV light. Once it's completely washed out and you can see, hopefully this is clear, you can really see that our image is nice and crisp and there is that light passing all the through the screen, you can go back to your UV light, turn that on, and kinda keep cooking it for a little bit, I wouldn't really suggest that if this were much further gone, but for this one, this might be okay, generally, if something like this happened and it was tearing all the way through, I would just go ahead at this point and reclaim the screen, so you would use your emulsion stripper, go back to your sink, spray the emulsion stripper on, and then, degrade all of that emulsion, and just start the process over, and this happens a lot in silk screen printing because it's a really finicky process, and so once you get a little bit more practice under your belt and really have your darkroom set up exactly the way you want, this won't happen. When you're working with a new emulsion too, you're gonna need to test out different exposure times. The next time I use this emulsion, I would probably expose it a little bit longer, if I were shooting in this same dark room situation, so these are just things that you're gonna have to troubleshoot, try and find work-a-rounds, and don't be afraid to start the process over. This is really common, even for experienced printers, so we have, luckily, a second screen that we've already prepared and that we're ready to get started printing with, so we're gonna go ahead and move back into the studio and start that part of the process.
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Ratings and Reviews
Ariadny
Wow, that was a great course. Erin is clear, engaging and encouraging. I would loooove to see a follow up course with her that explores some of the more advanced silk screen printing techniques that she mentions in the last segment. Great job!
Ana
Recently got my Creative Pass and I decided to explore the Creativelive library out of my usual fields of interest. Saw the title of the course and I said to myself - what is this? I literally had no idea about Screen Printing and that was actually the main reason I took the class. In just two hours I went from not having a clue to understanding the process and imagining me doing it :)) I'm not sure it will ever happen but I really enjoyed the class. Loved the style of teaching, very calm and confident, as well as the moderator's and students' questions which were filling up the gaps.
Marsha Law
Erin is such an outstanding instructor. She's just so confident with her topic and with her ability to communicate. This class helped me realize that I'm not ready yet to start screen printing, which in my opinion is just as important as recognizing when you are ready to try something.
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