# Screen printing emulsion problem



## crujones (Sep 11, 2010)

Hi, I'm trying out the Diazo photo emulsion technique for the first time, and am not having good results at all. It's probably easiest to just show you the results and hopefully you'll have some answers for me!

http://img59.imageshack.us/img59/7391/small4l.jpg
It looked clean enough when I washed it out, but there were some blotches that peeled off where the emulsion had built up. Not a problem since I can mask them out. 

http://img121.imageshack.us/img121/2606/small2p.jpg
But after I tried printing, there were these weird spots that prevented the ink coming through. 

http://img192.imageshack.us/img192/3118/small3s.jpg
It almost looks like air bubbles or something trapped in there. 

http://img691.imageshack.us/img691/2866/small1e.jpg
The printed result.

Is there any way to use the emulsion remover on spots like that? I just don't know anything about this technique. 

I'm using: Diazo photo emulsion kit, Speedball Fabric ink, Speedball 12xx 124 fabric

Thanks for any help!


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## selanac (Jan 8, 2007)

I've never had luck with the Speed Ball Photo Emulsion.

How did you expose it, and for how long? What type of exposure unit or process did you use? 

If you expose it too long the emulsion will harden too much. 

Can you show us what the film or stencil looks like? Did you print your design on Film or a stencil cutout?


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## crujones (Sep 11, 2010)

Ah sorry I left that out, I exposed it under a 100W bulb from 11" away for 45 min.

[media]http://img828.imageshack.us/img828/9426/bulbsmall.jpg[/media]
The bulb unit.

[media]http://img834.imageshack.us/img834/184/templatesmall.jpg[/media]
I printed the design twice on transparencies using a laser printer, then taped them together. I also placed a sheet of glass over the top to hold it to the emulsion. Basically I did everything by the book according to all of the instructions I've read. 

[media]http://img411.imageshack.us/img411/2432/burnedsmall.jpg[/media]
I also did a test one before this and I definitely burned that one, it was under a 200W bulb for over an hour - that sucker was toast!

The thing that seems weird to me is that the screen appeared to be clean (1st photo in the 1st post), and that I couldn't see any emulsion residue in there until I tried printing.


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## selanac (Jan 8, 2007)

What are you using to wash out the emulsion after you expose it? Do you have a pressure washer?


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## crujones (Sep 11, 2010)

Just running it under a sink, I don't have a pressure washer.


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## selanac (Jan 8, 2007)

You can get a sink to whose attachment for about $10, and a Pressure Water Attachment for the sink. It's one of those, As Seen On TV contraptions. I bought one for $20 at Staples and it works great. 

You probably need a little more pressure to wash out the rest of the gunk. Do you have a scoop coater? Look for a local screen printing supply store. In my opinion, I would get one. It saves a lot of time. I only coat the back using the scoop coater. It looks just like on the How To Videos when you're done.


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## crujones (Sep 11, 2010)

Thanks for the tips. Maybe tomorrow I'll just try taking it outside & blasting it with a hose on jet mode. I'm kind of reluctant to spend any more money on this emulsion method considering I'm already in it almost $100. If I can't get it cleaned out I might just switch to a Mask-Ease style film since it's not that complex of a design anyway. This photo emulsion stuff is just too many extra steps for an accident-prone guy like myself...


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## ehadden1 (Apr 12, 2009)

Get a 500watt work light(cheap) remove the glass from the light and hang it 18 inches above it for the right amount of time. Rinse is out real good with a garden hose. Good luck.


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## bomber315 (Jun 18, 2010)

you gotta have a scoop coater, i cant imagine doing it without one... the weird spots that prevented to ink from coming thru are diazo (i believe) from not rinsing enough... it dries in the mesh and cloggs,,,, i have some problems with that and generally i try to blow all the water out of the mesh before it dries so i dont get those... but im new too so maybe someone else knows a better way


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## selanac (Jan 8, 2007)

If you expose the screen with a Halogen 500 watt shop light at 18 inches above, you also need a piece of glass to put over the Film and Screen. Expose for 12.5 minutes. Don't expose longer, cause it hardens the emulsion. 

I know you're reluctant to spend a little more, but you can buy a hose for $10 or less. You don't even need a long house. I found a 15 foot hose for under $10. You'll also need a Faucet to Garden Hose attachment. That's also about $10. So, you only need to spend $20 more total. Two or three t-shirt sells and you made your $20 back. Ten to twelve and you made all your investment back. 

You can probably buy a hose at a yard sale for $2.00, then replace the rubber washer.


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## crujones (Sep 11, 2010)

Thanks for the help guys. I _finally_ got it working, but it wasn't easy. After one disastrous attempt at re-using the fabric, I gave up and tried a 5th time. This time I really worked on getting a nice even coat of emulsion with the squeegee by alternating from front to back, and by not applying more - just working it around until it looked even. 

I exposed under a 200W bulb )18" away or so) for about 20 min. (still too long I think) and it came out nice except for one spot where the emulsion was burned into one of the letters. 
[media]http://img194.imageshack.us/img194/2654/001hk.jpg[/media]

Used emulsion remover to get it out (this took a LOT of working with a toothbrush):
[media]http://img821.imageshack.us/img821/2374/002ieq.jpg[/media]

Then carefully added screen filler around the edges:
[media]http://img684.imageshack.us/img684/935/003zlc.jpg[/media]

It's not perfect (theres a little fuzziness on those edges) but is actually not that bad.


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## selanac (Jan 8, 2007)

Looks good dude. Seriously though, I would get a scoop coater. Then you just bang out a coat from the back. Just one time and you're done. 

If you get a hose attachment for your sink, and a small hose, you can wash out the screen easier. 

I also use a screen wash that cleans the screens in minutes. I use a spray bottle, and a scouring pad with water, and bam the emulsion comes right off. 

The speedball stuff is great to get started, but makes the process much longer. Why kill yourself when you can make a few changes and speed up your whole process. 

Best of luck to you.


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## pukingdeserthobo (Jun 3, 2008)

do your screen have good tension ? what kind or mesh are you using>?


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## crujones (Sep 11, 2010)

Argh. I thought I had this problem worked out. I finally got the design to work fine & printed off a dozen or shirts off it with no problems. Example of how it came out:
[media]http://img831.imageshack.us/img831/7527/shirt2r.jpg[/media]

After it was washed & dried I went back to it to do some more, and now the ink is blowing right through the edges of the design. The worst part is that there's no consistency _where_ it's doing it, so it's hard to know where it needs to be fixed. These were tests on paper (I washed & dried out the fabric between tests):
[media]http://img299.imageshack.us/img299/9753/test1de.jpg[/media]
[media]http://img688.imageshack.us/img688/9039/test2gx.jpg[/media]
[media]http://img691.imageshack.us/img691/2258/test3wn.jpg[/media]

Any suggestions on what might've gone wrong?

On a side note, I did another design using Mask-Ease film (which really only works for simple designs) and that works great - no problems whatsoever! I could just start over using that, but I was hoping to re-use this design since it _was_ working!


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## selanac (Jan 8, 2007)

I think it might be your off set. Should be about an eighth of an inch. Try putting pennies on each corner of the screen, and try again. 

You can also recoat the screen and expose it again. Don't forget ink dries. So, if you're using Plastisol you need a Curable Reducer, and if you're using Water based Ink you need a Retardard or Glycerin.


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## Greatzky (Jan 28, 2009)

the stuff blocking your image that looks clear is probably the left over diazo from the emulsion. It looks like there is just water left in your screen so you won't notice it until you dry your screen and then it will still be there. 
Best thing to do is blot the image area with papertowel or a lint free rag/towel until all of the water/diazo is out of your image.

That would be my guess as to what is blocking your screen.

-Scott Lewis
Silk Screen Expressions
Hyzer Flip Disc Golf Apparel


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## crujones (Sep 11, 2010)

Hmm not sure why the images didn't show on that last post, but it was a different problem than before. The ink was blowing out past the edges of the design. However, I went around the whole design on both sides with screen filler, let it dry & tried again. That seemed to do the trick, so it's working again. 

Thanks again for the helpful suggestions. It's hard to say what was getting stuck in the design before - water or diazo, but no amount of spraying/scrubbing/wiping got it out. If it's just a few small spots I just hand-brush the ink on those spots after it's printed & that seems to work okay.


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## dheadri (May 24, 2012)

Ok get the scoop coater and maybe some rip software and build your own light box to expose screens with, here is a good start on how to do that How to Build an Exposure Unit | American Screen Printing Association (ASPA) | Learn silk screen printing, tshirt printing
you can get a good rip software here for a inkjet advancedtshirts.com - Products List
if you are going to use a laser make sure you spray your film with toner aid after you print it so it will darken up.
it looks like your screen is not coated correctly and you are getting undercutting from you light source because you do not have positive contact and you are under exposed invest in a color change emulsion they have them I use nazdar and it is green when it goes on and blue when exposed. That will help with almost all the probs i see in your screen. Make sure you add weight to hold your screen and film positive to the glass on the exposure unit put a piece of foam a board and a weight on top to keep good positive pressure.


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## gographics (Mar 23, 2012)

Looks like you burnt your screen too long?


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## dheadri (May 24, 2012)

gographics said:


> Looks like you burnt your screen too long?


I think it is under exposed due to the amount of diazo left in the screen and you can see the water ran between the screen and the emulsion and it washed out of the thick areas. you can see the emulsion application left ridges in his emulsion where it was built up to thick. A scoop coater would help get rid of all the ridges. The washout technique was not good either you can see the washout was done with no pressure at all a garden sprayer would help a ton.
A pressure washer would be good but unnecessary because you can get along with out one. But a exposure unit is a necessary to get a good image they can be cheap to build yourself or go to ryonet and buy a inexpensive one Screen Printing Silk Screening Exposure Units


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