# Still having exposure problems



## Jmanindie93 (Apr 12, 2011)

So I recently bought a dehumidifer. I am coating my screens in my bathroom. I coated 3 screens 1/1, and stacked them with a 1x1 in between each screen so air could get under each one. I had a 20" box fan on low next to the screens. My thermometer/hygrometer currently reads 29% humidity and 93 F. Last night when I coated it was about 30% and 88 F. The normal temp is about 75 F, but the dehumidifier greatly raises the temperature. I let the screens dry overnight, but they were actually dry to the touch in about 20-30 mins. I noticed they were dry, but still felt a little tacky. If I pressed my finger against the mesh it would feel just a little tacky. This is how it felt before I got the dehumidifier and I though it would fix that. This was also with Ryonet's HiFi Photopolymer emulsion. I have a new thing of Diazo DXP as well, still haven't mixed it though. Anyways, I taped my positive to the screen, placed my glass on top of it, and set it under my 500w exposure unit from Ryonet for 8.5 mins. I brought it outside and soaked the image in water for a few, then tried high pressure. It wouldn't start to washout at all. I have to put the pressure nozzle so close to it that it blows the image out and takes emulsion out wherever it hits. Can anyone help me here? Is my room too hot? Thanks.


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## InkedApparel (Mar 18, 2009)

you say you are going utside to washout the screen..how long is it in the sun before you spray the screen with water? you should spray the screen before taking it outside....what is probably happening is the image area is getting exposed before you hit it with water.

Inked


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## Jmanindie93 (Apr 12, 2011)

I carry it out and immediately rinse it. before I bought the dehumidifier I had also tried carrying them out in black trash bags. Did the same thing. So currently the dehumidifier did nothing but dry them 10x faster.


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## sweetts (Apr 4, 2010)

Try 12.5 minutes on exposure time


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## Jmanindie93 (Apr 12, 2011)

Before the dehumidifier I had tried exposure times from 8 to


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## Jmanindie93 (Apr 12, 2011)

Before the dehumidifier I had tried exposure times from 8 to 30 mins. All did the exact same thing. Blew out from getting too close.


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## Pvasquez (Feb 19, 2011)

Jmanindie93 said:


> I carry it out and immediately rinse it. before I bought the dehumidifier I had also tried carrying them out in black trash bags. Did the same thing. So currently the dehumidifier did nothing but dry them 10x faster.


I hate to point out the avious but that's what a dehumidifier is supposed to do, if your a high volume shop not only do you want to dry your screens fast but you want to control variables and that is one of them to get consistent results. Why not just for the fun of it wash it out in the tub and see if you get good results, it's the sun that's affecting your screens and you should be able to develop in a few minutes. If your using an SBQ then I would have to guess that your film is not dark enough or your exposing for too long. 500 watt bulb like a flood lamp might also be getting your emulsion really hot and heat will cause emulsion to pre-expose as well. Your spending too much time in developing and you say that you have to get right on it this tells me your having trouble developing and your causing it to breakdown. I hope this helps but try it for 3 minutes and develop in the tub with the shower head.


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## Jmanindie93 (Apr 12, 2011)

I could also go outside in the dark. That'd work.


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## Pvasquez (Feb 19, 2011)

Jmanindie93 said:


> I could also go outside in the dark. That'd work.


Yes that would


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## Challenger (Nov 30, 2007)

Hello Mr. JMan, it sounds like your screen are getting fogged before you burn, or your glass is not making enough pressure to make a tight contact between the positive and your screen, and you are getting scattering when burning, it means the light is filtering between your positive and the screen.
Hope this can help you.
Challenger


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## Jmanindie93 (Apr 12, 2011)

Challenger said:


> Hello Mr. JMan, it sounds like your screen are getting fogged before you burn, or your glass is not making enough pressure to make a tight contact between the positive and your screen, and you are getting scattering when burning, it means the light is filtering between your positive and the screen.
> Hope this can help you.
> Challenger


What exactly do you mean by scattering?


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## Pvasquez (Feb 19, 2011)

You still having problems? Are you putting something under the ink side of the screen? Like a dark pillow or something? The scattering that he's talking about means if you don't have a good sandwich from the inside of the screen to the screen itself then the film then the glass you will have light sneaking in or bouncing back and exposing the whole area.


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## selanac (Jan 8, 2007)

Jman, with a 500 Watt exposure unit, your film/screen needs to be about 18" from the light. After 12.5 minutes of exposure time, take the glass and film and set them aside. 

Soak or spray your screen and let it sit for about 4 minutes. Then wash out your screens.


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## Challenger (Nov 30, 2007)

Hi Mr. Jman, it means your light is undercutting the film passing trough in between your positive and the screen sometimes making a severe screen exposure, so it is very hard if not impossible to develop a screen, as you described, please search with google and read about light scattering here is one Technical information on exposing StencilPro
hope this can help you.


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## Jmanindie93 (Apr 12, 2011)

My exposure unit is about 13" above the screen, that's how they are from Ryonet. And it is on my carpet with nothing dark under the screen on the squeegee side.


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## Pvasquez (Feb 19, 2011)

Jmanindie93 said:


> My exposure unit is about 13" above the screen, that's how they are from Ryonet. And it is on my carpet with nothing dark under the screen on the squeegee side.


Ok so get a piece of foam that is thicker than the inside depth of the frame cut it to fit on the inside and lay a piece of black fabric put your screen on it then your film and glass and this will prevent undercut and any light bouncing back inside and pre-exposing your screen. Almost there


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## selanac (Jan 8, 2007)

Have you tried an Exposure Calculator? They cost about $30, and could save you a lot of time.


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## Alan Buffington (Oct 27, 2010)

Pvasquez is on the right track.
Here are a couple of pointers:
May have been covered, but I'll give my 2 cents from beginning to end.

1. Coat once on both sides with sharp edge of coater using firm pressure since you have a low wattage light source and store in a light safe environment, put folded yellow mesh over any windows, may not block all light but better than none. Use bug lights where possible for incandescents, or fold up some yellow mesh and put over any fluorescent lights so it doesn't touch the bulb. Otherwise you will start exposing the emulsion as it sits in a room lit with white light.
2. Keep using your dehumidifier, they help you shoot a better screen since the emulsion is dry. Moisture in the emulsion prevents exposure.
3. As mentioned, piece of foam and black t-shirt over it, get good contact between film and screen with weights or pressure
4. Get as black an image as possible on your art, vellum can be used, but you will underexpose to get an image as your light will burn through transparent areas and expose the emulsion. If you can see through your film it is not black enough. Use lacquer spray (cheaper) or toner enhancer to increase the d-max (light blocking ability of the black area) on vellum.
5. Run a step test, go to: double U double U double U dot murakamiscreen dot com, its on the home page on the right.
6. Never develop or carry a screen in sunlight. The emulsion will expose wet or dry in under 10 seconds, thats a really strong light source in the sun. Send me a message I'll send you a sun exposure unit drawing, beats the heck out of what you are using now when the sun is out. Try 30 second exposures, excellent detail.
7. Develop in a lightsafe area. Your tub is a better choice with yellow light or do it outside at night. 
8. If there is slime on the inside of your screen during development it's underexposed.
9. If you can't hold detail after doing all this well:

Emulsion is not emulsion, check around.

Alan


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## Jmanindie93 (Apr 12, 2011)

I have a 21 step exposure calculator, which according to it I need to expose for 30+ mins, which I tried. Same results as 8 mins of exposure. I talked to Ryonet's support person and they said that to have a solid step 7 is only for halftones and that for spot colors it should be a solid 3-4, which I achieved with 8.5 mins. My first screen exposed fine, that was it though. Only that first one did, and that was before I had the dehumidifier. I think that the Diazo DXP will yield better results for me. It is still unmixed.

There is no light at all other than one yellow light in my bathroom. The windows are covered in foil.

If I lay my positives on a table it is very black looking and you can't see through it. If I hold it up to a light you can see through the black ink on it, but it is still pretty opaque. I am using a Epson 1100 with the ink that came with it using the best photo and premium glossy photo paper options. My glass piece I place on it for positive contact is 13x18 I think. I had it cut at Lowes.

For questions, how will the foam stay inside the screen if it is upside down exposing? And should I place my exposure unit in the bathroom too? Or leave it in the room right next to it (my bedroom)? I will try to expose in my room, spray all over with water, let soak for a few, then take it outside in the dark and attempt again. The only thing I don't understand is how when I expose it for 30 mins, the high pressure washer can remove the exposed areas. I thought it wasn't supposed to be able to do that. Will all emulsion do that if you get the spray wand close enough? Thanks everyone for helping me here. There has been some good ideas so far.


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## DecalDesignsGirl (Jun 3, 2011)

Possibly a dumb question, but are you sure the glass you bought is NOT UV blocking? You need to be sure to ask about that when you get the glass. 

Did you use the glass on the exposure that was successful? 

Could your emulsion been exposed? (possibly by someone else, I mean. Not you.)


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## Tshop1 (Jun 27, 2011)

Jmanindie93 said:


> I have a 21 step exposure calculator, which according to it I need to expose for 30+ mins, which I tried. Same results as 8 mins of exposure. I talked to Ryonet's support person and they said that to have a solid step 7 is only for halftones and that for spot colors it should be a solid 3-4, which I achieved with 8.5 mins. My first screen exposed fine, that was it though. Only that first one did, and that was before I had the dehumidifier. I think that the Diazo DXP will yield better results for me. It is still unmixed.
> 
> There is no light at all other than one yellow light in my bathroom. The windows are covered in foil.
> 
> ...


The foam will not stay inside because the screen is upside down? Is the squeege side facing up or down?


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## Pvasquez (Feb 19, 2011)

Assuming you have one of those exposure units that is a halogen heat lamp on a stick with feet for it to stand on and the light points down so do this.








Let's pretend my floor is your carpet and lay the foam down as shown above 








Cover the foam with a dark fabric or a black tshirt 








Put the screen over the foam then your film and your glass








As you can see your foam should be thicker than your depth of the frame so it should be hovering so you get a good sandwich and prevent light to sneak in.

If your having to expose for 30 minutes that's just crazy get yourself the right emulsion or go to a local screen printer and have them burn your screens for you. Good luck and hope this helps


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## Jmanindie93 (Apr 12, 2011)

The only problem with that is that I have to lay the screens on the pvc legs that stick out ofbthe exposure unit. So I couldn't set the foam on the floor. Im pretty sure the glass isnt uv protective. I get the same results without the glass.


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## Jmanindie93 (Apr 12, 2011)

I can add that the glass on the halogen light is uv blocking. You are supposed to leave it on but you can take it off to they say.


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## GrapeCloth (May 20, 2010)

Did you remove the glass covering your light on the underside of the ryonet lamp?


Live The Good Life.
www.GrapeCloth.com


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## GrapeCloth (May 20, 2010)

If you tried that, best bet is to use foam with a shirt and then do s step test. Is the emulsion old? Did it need additives? Could they be old?


Live The Good Life.
www.GrapeCloth.com


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## Jmanindie93 (Apr 12, 2011)

I did not remove the glass on the lamp. Should I? The emulsion is maybe 1-2 months old. Its supposed to last 18 months. My dual cure diazo is still unmixed though, which would probably be easier for me since I am new to this. But still it should work with this emulsion too. Do I still have to mix the presensitized photopolymer emulsion before I use it? Or only if it has diazo in it?


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## Alan Buffington (Oct 27, 2010)

Is the old emulsion you are using a pure photopolymer? 12 mos is quoted as the shelf life of a pure photopolymer, anything with diazo added is good for 4-6 weeks when stored below 80 degrees, longer if you refrigerate, just warm it before using or it will be too thick.

You need foam. Cover the legs with a piece of plywood, place foam, a piece of black t-shirt fabric over it and then check to make sure your positive is pushing up against the glass and is completely flat. If you are doing all this in yellow light and you still don't get an image, then look at these areas, some of which have been covered.

1. Screens are getting slighly exposed during storage
2. Image is not black enough on your film. If you can see through the black areas light is also going through and may be exposing your screen. Typically the drivers you mention do not produce good solid black positives, but grey positives which can allow light through exposing the screen. Stet test.
3. You may be developing screen outside? 5 seconds is all it takes, wet with water or dry, to expose SBQ emulsion.
4. Your film may not be making good contact with glass, although something should be developing.
5. If all this fails try your new bucket of emulsion with sensitizer mixed in.


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## Jmanindie93 (Apr 12, 2011)

Number 3 sounds very possible. It sits outside for a few mins soaking, although not in direct sunlight. But if it only takes 5 seconds then I doubt it matters whether its in the light directly or not. 2 and 4 are probably somewhat true as well.


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## selanac (Jan 8, 2007)

No those aren't your problem. You said you didn't take the Glass off the Lamp. 

The Lamp glass HAS TO COME OFF. It has UV protection which is blocking the UV. 

Next is your Emulsion. Buy an Emulsion that is premixed so you don't have to mess with mixing it. 

Make your life simple. Again, Take the Glass off of the Lamp. 

Will you show us a picture of your Image?


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## Jmanindie93 (Apr 12, 2011)

Currently I dont have any screens left with emulsion on them. Im coating tonight and will post results. Ive heard about people taking the glass off, but Ryonet says you can do either. I will take it off though.


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## selanac (Jan 8, 2007)

Could you post a picture of the Emulsion Container and one of your Image on the Film not the Screen. 

Yes, take off the Glass. I have the same setup from Ryonet. They told me to take the Glass off. I don't know who told you differently because the glass on the Lamp is UV protected. 

What are you coating with? Do you have a Scoop Coater? If so, use the thin side of the coater. If you don't, get one.


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## Jmanindie93 (Apr 12, 2011)

I have a scoop coater. My intentions are to coat it 1/1, ley dry, then coat again on stencil side, dry, then a third coat, all with the rounded edge of the scoop coater. That is how Ryan did it in the advanced white video. I do not want to flash in between prints. Why do you say use the sharp edge?


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## selanac (Jan 8, 2007)

I mentioned using the sharp edge cause it's less emulsion. You're putting on too much emulsion. 

We only put 1/1 and that's it. Let it dry, and expose it. 

The heavier the emulsion the thicker the ink is going to be. A thick coat of ink will give your t-shirts a Heavy Hand (rough heavy feeling). 

Many customers don't want a heavy hand.


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## Jmanindie93 (Apr 12, 2011)

I notice my ink is rough and not smooth with 1/1 when I have to flash. Even when I let it cool down. Why do they say to coat it heavier for white? Even bill hood does.


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## DecalDesignsGirl (Jun 3, 2011)

Terry Combs says 1/1, thin side of the scoop coater too. The amount of emulsion you're applying could help explain why the screens feel tacky too. (I don't think you used that word, exactly, but there was some comment about not feeling truly dry.)


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## Jmanindie93 (Apr 12, 2011)

They always felt that way with the sharp edge too, but that was before the dehumidifier was in the situation.


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## selanac (Jan 8, 2007)

The more emulsion you use, the heaver the ink is going to be. The ink fills the depth of the emulsion you laid down. 

If you have a thick ink it's also going to be heavy. Did you stir the ink before you used it? Stir it until it's creamy, before each use. 

Bill Hood, that old fart! 

If you're doing what they tell you, and it's not working than somethings wrong with what they're telling you. 

You should expose the screen for 12.5 minutes or 13 minutes and no longer. Take the glass and film off the screen. Wet the screen on both sides, and let it sit for 4 minutes. Then washout the screen on both sides.


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## Jmanindie93 (Apr 12, 2011)

Its ryonet white, no I didn't stir it. I dont know why, I knew that too, I feel dumb now. So you all support flashing in between prints?


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## selanac (Jan 8, 2007)

No one said that. 

If you do flash between prints when using white ink only. Only flash for about 5 to 7 seconds. You really don't need to flash when you're using the same color. 

Since you're using a Dehumidifier, where do you live? Is it really humid there?


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## Jmanindie93 (Apr 12, 2011)

Southern oregon. Humidity is around 50-55% on average.


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## selanac (Jan 8, 2007)

Not sure you need a dehumidifier. We're NE Part of U. S. And 84% humidity at 2:30 am, 

I'm sure the issues are the Glass on your Lamp and amount of emulsion Your using.


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## Jmanindie93 (Apr 12, 2011)

The emulsion feels the same with or without the dehumidifier. Either way it isn't a bad investment. Dries screens in 30 mins compared to 10+ hours that it took before. I just coated 6 screens 1/1 with the sharp edge. All done with the last of my HiFi emulsion. The guy from customer service told me it takes between 8-10 mins to expose with my setup for this emulsion. I don't know if he meant with the glass on or off of the lamp. What do you recommend trying for exposure times? The lamp is about 13" above the screen and I will be sure to remove the UV filter glass. I did my best job coating. Firm pressure, and the scoop coater slipped a little on each side going up, meaning it didn't stay evenly flat across the whole time, but they look pretty smooth still.

On a side note, I went and saw Joan Jett tonight and shirts were $25. Cheap stretchy Gildan Softstyles with a blurry print. Not sure if they were screen printed though. What a markup though. I'd like to pull in that kind of profit.


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## selanac (Jan 8, 2007)

You can use a regular house fan to dry your screens. They take about the same amount of time. However you already have the dehumidifier so you might as well keep it.

Bands normally get the t-shirts for a few dollars in another country. Of couse they buy a million at a time. Give or take one or two t-shirts. Lol.


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## Jmanindie93 (Apr 12, 2011)

The group selling them were from here they said and not connected to the band. That'd be good business to deal with. Tonight I am exposing with the glass off. Ryonet's customer service said 5 mins.


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## selanac (Jan 8, 2007)

That's 5 minutes for the Table top Fluorescent Bulb model not the Halogen Lamp Model. Here's a YouTube Video. This is the one you have right?

[media]http://www.youtube.com/watch?v=okKvOuamJd0&feature=related[/media]


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## Jmanindie93 (Apr 12, 2011)

I told them I had the 500w stand. Thats the one.


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## selanac (Jan 8, 2007)

Jmanindie93, I have the same one. Also Customer service people aren't screen printers. They probably never screen printed outside of the class room.

I still have that unit, but have two others too. 

Did you watch the video and hear him say 12.5 minutes?


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## Jmanindie93 (Apr 12, 2011)

Thats the video that had me confused on the DVD. He left the glass on for "demonstrative purposes", lol. That was with the dxp emulsion though right? I used my HiFi photopolymer.


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## selanac (Jan 8, 2007)

Jmanindie93 said:


> Thats the video that had me confused on the DVD. He left the glass on for "demonstrative purposes", lol. That was with the dxp emulsion though right? I used my HiFi photopolymer.


You're talking about the guy on your DVD right? I re-watched the video I sent you and he didn't say anything about taking off the glass for the exposure lamp. 

I'll have to watch the one on the DVD this weekend. I have the set too.


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## Jmanindie93 (Apr 12, 2011)

Yes, screen printing 101.


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## Jmanindie93 (Apr 12, 2011)

Just exposed for 10 mins with the hifi emulsion. I figured I'd start there. I got about a solid 6 on my 21 step calculator. The 5 and 6 were more transparent compared to the 1, 2, and 3. So according to it, I need to go for 14 mins. I think I lost a little fine detail, but I have to compare it to the transparency to tell for sure. I will try 12.5 mins. I think that should do it.


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