# Murakami's Photocure BLU Emulsion



## ryandubbau (Sep 21, 2006)

hows it goin ,

well the past few days i have been driving my self nuts trying to expose a few screens using Murakami's Photocure BLU emulsion. no matter what times i have tried (anywhere between 25 secs. to 2.5 mins) i cannot get the image to blow out in any of my screens. 

here is a link to my exposure unit i am using so you can get an idea of what im working with and what could be going wrong. 

Automated UV Exposure Unit Large 25x36"

i have tried exposing a 110 screen, a 125, and a 156 multiple times and have not been successful with any of them.

here is what i am doing:

handling and burning the screens all in a light safe room, 

stepping out in a shaded area to rise off the screen, 

i am using a 1200psi pressure washer, i spray down both sides then let it sit for 30 secs.

after about 5 minutes of spraying parts of the image begin to blow out , 

but then the emulsion itself begins to rip off in pieces intacted to the areas that the image is blowing out at.

after this stage the emulsion just beings to rip off the screen.

i am holding the pressure washer a reasonable distance away, and when i move it closer the emulsion doesnt stand a chance of course.

what is confusing me is the image isnt really blowing out nicely like past emulsions i have used (prochem dxp pink)

this emulsion is more so riping out and tearing apart, and when i use a regular garden house it doesnt even phase the emulsion.

i dont believe my films are a factor to this problem at all either, they are extremely dark, i had them printed on a Epson Stylus pro 9800

sorry for the long post, just want to give you guys some detail to my process to see if you could help me any way because i am begining to go nuts.

appreciate the help and time, 

thanks!


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## ryandubbau (Sep 21, 2006)

i also forget to mention in my post that i am only coating each side of the screen once, with the first coat on the printside and then the second coat on the ink side. i also am using weight on the inside of the screen. i cut out 3 inch tall compression foam to fit the inside of the screen and put a piece of plywood on top with weights evenly distributed. total weight i am using is 50 lbs. the film is getting positive contact between itself and the screen, and i do see the image in the screen once it is burned, i just cannot get it to blow out. even at a 30 sec exposure the emulsion isnt running or blowing out like it is under exposed, so thats why i havent tried exposing it longer. 

any input on this would be appreciated!

not use to this new emulsion, should i try bumping down my exposure times even more? 25-30 secs just seems so short to me, but then again i am use to 4-5 min exposure times.

thanks


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## darwinchristian (Aug 24, 2007)

hey Ryan. i use the same exposure unit and also a photopolymer emulsion. i use ulano's qtx. my burn times are 1min 50s, 1m 30s, and 1m 20-25s on meshes 110, 156, and 230, respectively. 

the thing with a photopolymer is that your under/over expose threshold is very small... literally seconds can push you out. it is faster exposing than a diazo, but there's a brief learning curve.

i'd practice on your high mesh so as not to waste so much emulsion, and start a series of step tests. make notes of your results, you will find the threshold.

derek.


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## tman07 (Nov 14, 2007)

Sounds to me you are trying all the right things. 

If you have gone down to 20-30 seconds and it won't wash out, you might have some bad emulsion.

If the image won't wash out and you are using a good, dense positive, it is hard to over expose because the light does not penetrate a dark positive the way it would a poor quality positive, like vellum. 

I would check the pot life of the emulsion with the manufacturer.


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## ryandubbau (Sep 21, 2006)

thanks guys for the responses. I just bought this emulsion 1 week ago. It has been getting cold here at night (mid to low 40s) but I store it in the box inside of an insulated room that doesnt reach the 30s. Do you think the cold has a factor in this at all.

I'm just trying firgure out what the problem is and how I can get my screens burnt asap. 

Thanks again for your help


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## SUPREMEPRINTS (Dec 12, 2007)

I also use Photocure blu. I have a homemade light box with two 275 watt movie bulbs. I expose for about 1min.15 to 1min.30. I can't use a pressure washer inside so believe it or not I use a spray bottle to spray out my design. It works for me. Seems like the longer the BLU stays wet, say 5 or 10 minutes, it does start to break down. I usually reclaim my screens outside with a pressure washer.


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## ryandubbau (Sep 21, 2006)

alright cool im going to give that a try, i usually just let it sit for about 30 secs after i initially spray it, ill wait for about 5 mins then try to blow it out.

thanks!


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## INKSCREENS (Jan 28, 2008)

ryandubbau said:


> alright cool im going to give that a try, i usually just let it sit for about 30 secs after i initially spray it, ill wait for about 5 mins then try to blow it out.
> 
> thanks!


Do not use a spray bottle to spray out your design. That is a waste of time!!!!!!!!! Don't use a pressure washer - it will most likely ruin your design as it has too much power. Buy a hose attachment with different levels of pressures.

Do not wait 5 minutes. That is an excessive amount of time to wait. Instead, after exposing, get both sides of the screen wet and let sit for a 1min. Try washing it out then. (I don't think this is your problem though).

Cold weather should not be a problem between 30's - 40's, cold emulsion is better than hot emulsion. Our shop keeps emulsion in the fridge. Burn times depend on the mesh count you use as well.

How are you drying your screens after coating it?

Another hint: If the design or emulsion itself doesn't blow out, then it probably means you're OVEREXPOSING. Shorten your burn times if that's the case.

If the emulsion is still goopy when blow out time, your UNDEREXPOSING, lengthen burn times.


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## SUPREMEPRINTS (Dec 12, 2007)

I meant if it takes 5 min to wash out it starts to blow out and lose the image. I only let it set about 30 seconds before I spray it out. As far as a hose attachment goes, the water pressure where I work stinks. I dont think the hose thing would work. I'm just trying to work with what I got.


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## kavemonkeyy (Nov 26, 2009)

Sorry to be so late on this, but I am hoping you made some progress on this.

I recently got Murakami's Photocure BLU Emulsion and am experiencing the same issue. I have taken my times down to a minute and I just can not get the image to blow out.

I was using a nonsensitive emulsion that I had to mix and it worked great. Only problem was it had a 3 month shelf life after being mixed. I thought I would try this Murakami's Photocure BLU Emulsion because it has a shelf life of a year. 

Have you had any success in getting this stuff to blow out?


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## red514 (Jul 21, 2009)

ryandubbau said:


> thanks guys for the responses. I just bought this emulsion 1 week ago. It has been getting cold here at night (mid to low 40s) but I store it in the box inside of an insulated room that doesnt reach the 30s. Do you think the cold has a factor in this at all.
> 
> I'm just trying firgure out what the problem is and how I can get my screens burnt asap.
> 
> Thanks again for your help


test the emulsion to make sure it's ok. Richard Greaves had a great suggestion on another thread of coating a screen, letting it dry but not exposing it.. just wash it out. If it's not washing out with this test you know something is wrong with your emulsion.


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## out da box (May 1, 2007)

Photocure blue is a sbq high solids emulsion. It is tricky to burn correctly. The blowing out is because of underexposure and too thick a stencil. The high solids content makes the emulsion build up alot faster so you'll get a much thicker coat with less passes. Get your stencil as thin as possible then work your way up when you can get your exposure and detail where you want it.
Oh yeah, SBQ emulsion does not like a weak light source.


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## nation03 (Sep 2, 2008)

I have the same emulsion and same exposure unit. I use 5 minutes for almost everything and never had a problem. The only way you'll get quick burn times is on a metal halide. Try 5 minutes and you'll be good to go. I love this emulsion so far. Never had a stencil so thick before and it cleans, prints, and reclaims so much nicer then stuff I've used in the past.


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## RichardGreaves (Nov 7, 2006)

Acch. I didn't notice this is a Jan. 2008 thread.

For what reason would anyone wait 5 minutes to start developing each stencil?

Are you developing outside?

Exposure is easy. The purpose of UV exposure is to change the stencil from something that will dissolve with water, into something that *won't dissolve or breakdown with water*. If it doesn't dissolve, it adheres to the mesh. One or the other. Yes, you can blast the stencil with a pressure washer as the Hydro Blaster people taught us in the 1980's. Keep this in mind and your solution is clear. Tell everyone you know in town.

*The answer is in your hands. *
The only power you have to make your stencil survive EVERY step of the screen making process, is exposure.

If the stencil breaks down - it's under exposed.

*Establish a base time for development/washout*
Every stencil mesh, coating thickness, emulsion & water are different - so you should test.

Make a very small coating (3"x6"), on a screen and let it dry - then take it to the sink and time how long it takes to wash it out.

Don't expose it, just wash it out. That is your standard time for washout for that mesh & coating.

Watch the clock as you develop the screen. Average screens don't take longer than 1-3 minutes at most.

If you have areas of the screen that are hard to budge, you've had storage failure, and your room is not safe

Your problem could also be your positive is failing you, so you get bored and break out the pressure washer.

*Dime - Complete Opacity Test*
Next time you expose a screen tape a dime or a piece of aluminum foil to the stencil to see how the dark areas of your positive *compare* during wash out. No UV energy will penetrate the dime and it should wash out like a dream.

If the area covered by the dime doesn't dissolve, you've exposed the stencil to UV energy or heat energy when you dried & stored it and the stencil resists dissolving with water and going down the drain.

*What's your time worth?*
Soon you'll get bored with the person that trained you, or sold you an exposure unit or an emulsion and didn't tell you about, or sell you anything to measure the moving target of hand coated stencils.

* Homework*
Exposure FAQ Screen Making Products how to measure exposure


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## kavemonkeyy (Nov 26, 2009)

Thank you for the fountain of information Greaves. It is great to hear from a senior member on how to do an exposure test and to remind us all that any change in the exposure processes (new light box, new emulsion, new anything) will make a difference in our exposure times

Please forgive us newbs, but I think our frustration came from this particular product. I coated a screen a thin a possible with this Murakami Photocure blue and let it dry. My washout with out exposure was ridiculously long. I would rule out my dry box, my room lighting or anything else because I have had success for every other screen that used. 

I find that a dual cure emulsion does take longer to expose and has a much shorter shelf life, but in the long run is much easier for me personally to handle. 

Not that all presensitized emulsions are this difficult, but Murakami's Photocure BLU Emulsion is not a product I would buy again.


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## RichardGreaves (Nov 7, 2006)

I'm very pleased you did a 'washout without exposing' test. This is a test I suggest to test for storage problems. This usually discloses someone developing outside or they store screens near a garage door. Your situation is the first time I've heard that the stencil resisted dissolving without a problem, so I see your point.


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## kavemonkeyy (Nov 26, 2009)

Huge break through on the BLU Emulsion. Previously I did not have a washout booth. I would expose the screen, shut off the lights and get the screen ready to rinse.

THEN I WOULD GO OUTSIDE. even if it was for 5-10 seconds before I got water on it, the unexposed section would get slightly exposed.

I have since put in a washout booth and I am in dear total darkness when I wet the exposed screen. Since then, the washout has. been great.

I went from a hater to a fan just like that. it exposes MUCH quicker than dual cure, and the exposed screen seem harder lasts longer for longer runs.

Light?!?!?! Who knew?!?!?!


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## nation03 (Sep 2, 2008)

Yeahhh, I love this stuff. Can't say enough good things about it.


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## RichardGreaves (Nov 7, 2006)

kavemonkeyy said:


> Huge break through on the BLU Emulsion. Previously I did not have a washout booth. I would expose the screen, shut off the lights and get the screen ready to rinse.
> 
> THEN I WOULD GO OUTSIDE. even if it was for 5-10 seconds before I got water on it, the unexposed section would get slightly exposed.
> 
> ...


Not light, but *Invisible UV energy* of which the sun is one of the strongest sources. UV Energy is the only thing that causes the sensitizer reaction that cross-links and causes a chemical cross-link between the "PolyVinyl" components that make up the "emulsion".

Pre-December 2008 Murakami tech sheets used to have helpful coating pictures and storage instructions that said protect unexposed stencil materials from sunlight, normal indoor lighting and freezing - don't say anything like that anymore.

I suggest:

Store coated screens in a UV safe area at 59°F to 77°F (15°C to 25°C) at 30% to 40% relative humidity.

*UV Safe Light Posts*
http://www.t-shirtforums.com/screen-printing/t115372.html#post677901

http://www.t-shirtforums.com/screen-printing/t23724.html#post140633)

http://www.t-shirtforums.com/screen-printing/t82942.html#post489879)

http://www.t-shirtforums.com/screen-printing/t25983.html#post153633

http://www.t-shirtforums.com/screen-printing/t59472.html#post353417


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## Alan Buffington (Oct 27, 2010)

Hello everyone who has read this post. I am a technical sales rep for Murakami Screen USA, the distributor for this product. I apologize for being late to respond to this post but notice it still has recent hits. As the intial poster discovered it is difficult to wash out a screen if light from outside or reflected off a nearby wall, or sky light is present. On a 5kw lamp it exposes in 30-60 seconds depending on mesh counts.

SBQ washes out differently than a diazo emulsion. It is much stronger and the use of a 600PSI pressure washer on fan spray at 8-12" is the best tool to develop SBQ emulsions or a garden nozzle set to strong fan spray. Also mentioned here is that SBQ likes a strong light source, all emulsions do. You can still expose Photocure BLU on fluorescent systems as well as 1.25 Kw systems. 

Here are the correct links for this product on the Murakami Website:

Exposure Tips: http://www.murakamiscreen.com/documents/EmulsionExposureTipsOptimized.pdf

Exposure Lamp Comparison: http://www.murakamiscreen.com/documents/ExposureLampComparison.pdf

Step Test to Determine Exposure Time: http://www.murakamiscreen.com/documents/StepTestInstructions.pdf

I am also available by phoneto answer any questions regarding Murakami Products and Print Solutions
800-562-3534 ext 118
323-980-0662 ext 118
323-697-4334 

Best Regards,
Alan Buffington


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## red514 (Jul 21, 2009)

hi Alan! thank you very much for posting!


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## Alan Buffington (Oct 27, 2010)

kavemonkeyy said:


> Thank you for the fountain of information Greaves. It is great to hear from a senior member on how to do an exposure test and to remind us all that any change in the exposure processes (new light box, new emulsion, new anything) will make a difference in our exposure times
> 
> Please forgive us newbs, but I think our frustration came from this particular product. I coated a screen a thin a possible with this Murakami Photocure blue and let it dry. My washout with out exposure was ridiculously long. I would rule out my dry box, my room lighting or anything else because I have had success for every other screen that used.
> 
> ...


Hello,

Let me introduce myself first, and I realize this post is old, but I research all posts regarding Murakami as I am the sales person for this. 

this product is one of our most popular emulsions.
If you found it difficult I apologize for the experience. Send me an email so we can talk and help you through any issues you have had. Typically on a 5k system I can expose a perfect image, with great durability in 45 seconds.
Edge quality and resolution are excellent. So we need to find out more about your exposure methods to advise. I can dial in this emulsion on a 4 tube fluo box, the sun, a 5kw, or anything in between. 
[email protected]

Alan Buffington
Murakami Screen USA


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## speshoot (Apr 23, 2016)

kavemonkeyy said:


> Sorry to be so late on this, but I am hoping you made some progress on this.
> 
> I recently got Murakami's Photocure BLU Emulsion and am experiencing the same issue. I have taken my times down to a minute and I just can not get the image to blow out.
> 
> ...


sorry so late..but how was it goin with this?


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