Instructables

Screen Printing: Cheap, Dirty, and At Home

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Step 4: Burn Your Image

1. Once the screen is dry, take it out in the sun and lay it face down on a piece of black cloth. The back of the frame is facing up and the screen is flush against the cloth. You need UV rays to expose the emulsion. Even on a cloudy day, you can get exposure. A lamp at night will not work.

2. Now place your transparency (or bit of lace or leaves or whatever) on it, inside the frame and lay a piece of glass smaller than the picture frame on top of the image.

3. Leave it there for a while.

The sun is going to harden the emulsion. You'll notice it change from a lighter green to a sort of blueish color. Be careful of shadows. Even the piece of glass can cast a shadow. It's a good idea to carefully move the whole thing a little bit to avoid shadows. If you do end up with a shadow, you can always patch it up later by dabbing a bit of photo emulsion on the gap. Still, it's preferable not to have to do that.

Any part of the screen which doesn't get hit by the sun is going to wash clear. Be very careful not to let your image move around. The glass helps keep it in place and also makes sure no sun gets in under the edges of the image.

How long this takes depends on how much sun you've got.



 
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cladyire2 years ago
Where did you put the acetate or transparencies?ate the back or front?..
Hey, thanks for this! I bought a screen printing kit and nowhere in the instructions did it tell you what side to put the transparency on...or that you could use sunlight in less than a minute instead of using a 150 watt bulb for an HOUR. I just did it, and it worked perfectly. I have a few shadows from the glass and the frame, but those should be easy enough to patch up. Thank you!
ben2million3 years ago
Hi Tracy. I really love your stag transparency. Do you by any chance have a digital copy you'd like to send me? : ) ...
An4rkiss7 years ago
hello.. how do u get that super dark design on ur transparency ? is it must to have a very dark design on the transparency ?
tracy_the_astonishing (author)  An4rkiss7 years ago
The darker the better. Get your design photocopied on a transparency and make sure to turn the contrast all the way up. If the copy isn't really opaque, light will get through and your design won't work. You can also paint on a transparency, use cut out pieces of paper, or draw on a transparency with white out (these are ony a few options--you can really do a lot of different things.)
can i use tracing paper instead of transparency? can easily print designs to tracing paper.. will it effect the burning process ?
tracy_the_astonishing (author)  An4rkiss7 years ago
I think tracing paper could work, but I'm not sure. Try it, and report back!
It will work but you have to double the exposure time.
Hey how long exactly should the exposure time be? Cause I actually want to follow through with this for one of my classes.....
3kY An4rkiss6 years ago
Yes it will work. I use bond paper coated with cooking oil.
teraluna4 years ago
 Hi,
I am trying to burn my own screens.  I have 3 florescent 20 watt  bulbs.  Not black light bulbs.  I can't seem to figure out how long to burn the screens for after many attemps.  The fine details are staying on the screen.  Can anyone advise me on how long to burn the screen?

Tera
Tera, I just found this site, try it!!!
http://www.t-shirtforums.com/t-shirt-articles/t106506.html
Hi there.  This link shows 20 watt bulbs, but they are black light bulbs. http://www.screenprintingguy.com/exposureunit.html

Or there's this link:  http://www.ryanrss.com/Exposureunits.html  Read the paragraph, not buying the light table or anything...

OR There is always this link: http://www.screenprintingforum.com/index.php
Try that!!
alliemommy57 years ago
Wow! These are wonderful ideas! - I read on another site how to use glue to fill the void instead of photoez has anyone tried this, and if so, what was the outcome? Also, how about a cheap site to purchase the ink and photoez for a beginner that doesnt need gobs! I am mainly looking for white ink. Thank you so much for your time. -allie
Yes, in fact I use this for my art classes.  My students used only modge podge glue to create their entire screens. (we had inconsistent results with emulsifiers and it's cheaper)  So yes, glue can work as long as it is not water soluble after it's dry.  Don't use elmer's glue or tacky glue because it will become wet again even after it's dry.  
tmillet5 years ago
Awesome instructable, but I am having some troubles. I live in Utah, and we get quite a lot of sun here. I just barely got my screen and was trying screen printing for the first time. I put on the emulsion yesterday and let that dry in my closet overnight. This morning I woke up to clear skies and went out at about 11 and i had an image printed on a transparency that I just printed using my printer at my house (The image was black). Then I used a couple pieces of tape to keep it on the screen. Then I put it out in the sun for about 7 minutes. I took off the transparency and started to spray, and nothing happened. I sprayed for about 5 minutes and gave up. What am I doing wrong?
Over exposed.  To fix this, you'll have o play scientist with a control screen.  Get a screen and set your timer- put the screen out on a dark cloth, just as you would regularly, lay some button randomly down on the screen, and  have a  dark piece of wood or mat board covering the whole thing.  Slowly move the mat board back about 1-2" every minute or 30 secs, or how ever long you want.   the first will be expoosed the entire time, maybe 10 mintues, the second strip will be exposed for about 9.5 or 9 minutes and so on.  You will see when the screen was not exposed enough, when it was exposed too much, and everything in between.  It takes you being there while it's happening, but it's very informative and the buttons on the screen essentially act as the control, allowing you to figure out if it worked at all. If none of your buttons show up at all, your emulsifier is bad or was exposed to too much light while it was drying and is already hard.  hope this helps.
Tracy is right. 7 minutes is probably way too long for the intensity of the sun. Even on a cloudy day the UV rays are high. Cut the time in half and double up your films. Keep the screen out of direct sunlight (in a black garbage bag if possible) until the moment you ready to expose. You can rinse it in the shade or even in a garbage bag as well. Also after remove your film you should probably see a faint image on your screen after exposure. This is the unexposed emulsion that should be relative easy to wash out. If you don't see this at least after rinsing the screen and letting it set for a couple of minutes then the screen is probably over exposed. The unexposed area of the screen is more visible after soaking.
tracy_the_astonishing (author)  tmillet5 years ago
It sounds like your emulsion got exposed all over. You can save the screen by using the screen cleaner. It dissolves the hardened emulsion. Be sure to wash it once with mild dish soap after that and let it dry. Here are some suggestions for the next try: 1. You don't need to leave the screen overnight in the closet to dry. Probably about half an hour is enough. I like to point a small fan on it to make it go faster. Your screen may have gotten enough light over those hours in the closet to have been set before you even began. 2. Try doubling or tripling the printed transparencies. Even if they are black, some light can be getting through. 3. Try letting it sit in the sun to expose for a shorter time. Take a look at the color of the emulsion now. When it turns that color (from a lighter green to more of a blue in the case of the emulsion I used), rinse the screen right away 4. Rinse the screen in the shade. Good luck. Perservere! You will succeed.
trishieC5 years ago
I'm having a problem and trying to figure out what Im doing wrong. I spread my emulsion on both sides (it's pink-I got it at a print shop locally) and tried to scrape it pretty thin so I wouldnt overcoat it or make drips. I dried it in a cardboard box, laid the image on it, put it in the sun and counted to twenty then tried to wash it out with a gun nozzle on my shaded patio and the image just will not wash out. What am I doing wrong? Could my emulsion be too thin? Is this possible? Oh, for the screen fabric, I bought sheers at Target because I didnt have time to get to a thrift shop. help.
I might answering a day late and dollar short- but it seems to me from my numerous mistakes in this process- that you either overexposed it far too long- try less time under the light source-, or that the image wasn't completely flat to the screen and allowed some light underneath,  which happened once to me.  It looked fine, but then it wouldn't wash out.  Alo, put a dark cloth under you screen so no light bouncing back up at it from the wrong side.  I'm just guessing here.  Hope it helps.  Keep trying!
bergiemoore4 years ago
I discovered that you can add elmer's glue to a regular sheet of plastic (like a pocket protector or  transparent paper cover) and then send it through your ink jet printer!   Elmer's glue worked better the best out of modge podge, polymer gloss gel medium, or wood glue.  Since it took me  about 4 hours of drying and testing to figure this out, the world should know about it :)
residual5 years ago
Instructions are great, I followed them completely but still had some troubles. I exposed the screen to sun around 7 pm so the sun was not too strong so I thought I'd have to leave it for a bit longer, around 2 minutes. Design washed out, everything looked perfect until the moment I started printing. The ink just wouldn't go through! Is it possible that the thin layer of the emulsion is unwashed, but I can't notice it? The screen was bought from a screen printing equipment supplier and it's 42 w.
nune5 years ago
Sorry this might be a very dumb question. I don't really have a bathroom where I could use the power hose to wash off the screen. Would you recommend waiting till it gets dark to wash out the screen outside!? I couldn't expose it to any light during daytime correct!? I assume the emulsion can get pretty solid in a matter of seconds on a sunny day... Thanks so much for your help! This post is very enlightening!:)
revcdub nune5 years ago
Wet the exposed screen and let it sit for a few minutes, then take it out to finish with the hose.
tracy_the_astonishing (author)  nune5 years ago
I've cleaned a screen outside in daylight with a garden hose before. If you do it fast enough it can be fine, but I have had some frantic moments trying to get the last emuslion out. It seems like if your image on the transparency is really, really opaque and no light gets through, that is what matters most for being able to wash out the emulsion. If it has gotten a tad bit exposed already through the image, then you might have trouble. But I have washed emulsion out of a screen with a garden hose on a sunny day before, so it can work. The higher the water pressure the faster the emusion comes off.
wolfybrie5 years ago
I've just used a light kit, taken from an old lamp, with a pie pin as a reflector before and my shower to wash out the emulsifier. Never had any burning problems. At one point I had instructions for the distance from screen and time based on wattage of your bulb. If I find them again, I'll post them.
this is a very helpful tutorial, however I want to point out, if you are using the "curtain screen" material - you have to be careful when you expose it under a bulb and reflector, because the heat of the bulb can burn a hole in the screen. i found out the hard way : ( i'm waiting for a sunny day to try it out and compare to the expensive screen material.
Sunlight is definitely best. The light has to be UV, so all the time I thought I was exposing the emulsion with a light, really what was working was the sunlight coming in through the windows! If you are using a UV light, keep the light farther away from the screen and you won't have a fire. The expensive material will also burn if too close to a hot light. The real advantage to a more expensive screen material is that you can control the mesh size exactly, which can be important in some projects, but for quick and dirty diy stuff usually doesn't really matter too much.
omG this is so helpful i bought my boyfriend a $400 set to do this and it came with everything except the lights which were $600 alone , he doesnt know how to burn the image without lights and a dark room to do the emulsion step, this is awesome hes gonna be super happy 2 use this . thanx u r awesome!
harosef6 years ago
Hello, I have been trying this out and just have a question...can you give a ballpark length of time it takes to expose the screen in full sun? I am unsure how long to leave it...or do I take it off right after it turns blue? Thanks very much, this tutorial is great!
tracy_the_astonishing (author)  harosef6 years ago
If you have a sunny day and nice, fresh emulsion, it can go very, very fast. Like 20 seconds fast. If it's a cloudy day and maybe you're exposing your screens in the house, it can take a lot longer. What I do is I take an already-exposed screen and compare the color of the emulsion on the new screen. When it gets blue, I stop the process. If you expose it too long, some light can creep through the black part of your design and you might end up with parts that are hard or impossible to clean off. This can actually give a kind of cool effect sometimes, but I'm not so big on accidental cool effects, personally. Err on the side of too short over too long. If the emulsion has changed color, you're probably good. You can really tell if when you take to transparency off you can clearly see the image in green.
Arrgh4067 years ago
can you also use a flourescent lamp?
tracy_the_astonishing (author)  Arrgh4067 years ago
I don't know. Probably. Try it and report back! I have a halogen lamp I use on rainy days which works great, but you have to move it around to avoid getting a shadow from the edge of the piece of glass.
Only use a blacklight or other UV light like the sun. I was completely wrong about this, it seems. I thought the light I was using was burning the screen, but really it was just the sunlight coming in from outside.
KnoCloo277 years ago
This is an awesome instructable... Pictures are great! I really want to find the time to do some of this stuff! It looks like you can "burn the image" even faster with an unfiltered blacklight tube? I've got a blacklight... Have you tried one? And how fast does it burn the image? And for those of you reading this amazing tutorial, if you are in fact confused by anything, Speedball's own instructions for screen printing are on their website (www.speedballart.com). And if I was interested in just buying a silk screen, how would I go about choosing one? I know there are different thread counts and sizes and stuff. And bases on screens? Are they for registration marks? Thanks for all this, I hope I'm not annoying you with all my questions! Lol. In His grace, ~bryan
Thanks for the compliments. I'm glad it was helpful. I've never used a blacklight. I have used sunlight and a halogen worklight. Any light will do, but the brighter it is, the faster the image gets burned in. I don't know very much about store-bought screens. I haven't used one since screenprinting class! I'm sure you will find information online about that. Different jobs prefer different thread counts. The higher the count, the finer the holes, the more detail you can have.
I was totally wrong here about the light. It has to be uv. All the times I thought I was hurrying things along with my worklight, it was just the sunlight coming in through the windows that was doing the work. Now I feel dumb!
Cakemix7 years ago
Great instructable, I can't wait to start screening my own designs! One (well, really several) questions: when putting the image onto a transparency, is it possible to do so from an inkjet printer onto a transparency, or will that not yield a dark enough image? Do you need to ask at the copy shop to get your design copied to a transparency or can you just bring your own and feed it into the copier manually? And, lastly, what brand of transparency do you recommend? I've tried several types but the ink isn't sticking well enough, so I think I might be using the wrong type. Thanks much!
tracy_the_astonishing (author)  Cakemix7 years ago
You are best off getting a transparency from a photocopy place. They are really pretty cheap. Tell them to make the copy extra dark. I've never tried with an inkjet printer, but I can't imagine it would be opaque enough. Even with photocopies it has happened to me that the copy wasn't dark enough and not all the emulsion would wash out.
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