# Emulsion Challenge Ulano QX-1



## jemsart (Nov 5, 2007)

Okay, I've spent the past week trying to figure out what exactly is happening with my Ulano QX-1 emulsion. I have used this emulsion in the past with decent results so when I was handed a printing job QX-1 was my first choice.

I have read many posts on this forum surrounding the nightmares others have faced to gain a better understanding on what may be happening. 

I ran a test as I always do prior to burning my screens and judged an appropriate time range. When I actually burned the screens it showed it was terribly underexposed. So, I scrapped that and began again...with the same results. With great aggrivation, I ended up ordering more QX-1 wondering if I happened to purchase an emulsion that had reached the end of it's shelf life. (I worked in a camera store and understand about rotating stock and how at times, some products have sat longer than others.) So, the new batch arrives but I am experiencing the exact same results except the improper exposure varied between underexposure and overexposure.

I ran a test in just allowing a small strip to dry then without it being exposed, rinsed it away. My results indicated that my screen safe was keeping them unexposed.

I am now wondering if the halogen bulb is old enough in my light unit that the UV has diminished enough to give me this shifting time trouble. My next step is to buy a new bulb. In addition, I have ordered Lawson SBQ 510 since I have had good results with that in the past as well.

I did allow the screens to sit over night with a humidifier running as well as a fan on them so I do not believe the issue to be the screens not drying properly.

The image is printed with a laser printer on vellum paper and this method has always worked for me in the past. I'm thinking of spraying my art work with a fixative just to rule out the possiblity that the image is not dense enough to hit the proper exposure range. 

I managed to get one screen that was usable BUT there was a ding on one of the letters that required retouching after printing. ON 20 shirts that was not a big deal but the client has now ordered 80 shirts and I need a better screen to produce a better product.

Any other thoughts on what I may be missing here?

Thanks ever so kindly in advance.


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## macmiller (Jul 23, 2007)

This, by no means, is not the technical way to do it, but I say try doubling your exposure time, and work down from there. You won't hurt anything.

I see people have trouble here on the forum from severely underexposed screens, until that's fixed, it's hard to move on.


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## jemsart (Nov 5, 2007)

Thanks for the input. As per your recommendation, I will double the time and see where that lands me.


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## jemsart (Nov 5, 2007)

Here is a new clue to the equation: I went to reclaim the screens today and the screens with this batch of Ulano emulsion refused to rinse clean. Even with using a full force of spray, and plenty of reclaiming spray they are stained blue and locked up. 

I reclaimed some screens with Ulano that I had processed last year and those washed clean without much effort. Could this possibly be a bad batch of emulsion? (Or emulsion that had reached the end of it's shelf life.) I ordered twice from the same supplier but if it was from the same stock, I would just have twice as much product that would not work.

Tomorrow the Lawson emulsion should arrive. I guess I will find the answers I seek then.


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## macmiller (Jul 23, 2007)

QX-1 should last a year once opened, under normal shop contitions. With any emulsion, once the screen is burned, the image should last indefinitely and still reclaim like it should.

Are you using a pressure washer? Are you using any harsh cleaners that might lock the emulsion. QX-1 is pretty good with most "hot" solvents, but things can happen. Also an underexposed screen is probably the hardest thing to reclaim as the emulsion never cross linked. Search "Richard Greaves" on the forum. He used to work for Ulano and his posts are very informative (and I like his dry humor!)


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## jemsart (Nov 5, 2007)

Thanks Macmiller! I have read Richard Greaves' posts on here and his insight has been wonderful. The thing that confuses me about this Ulano experience is that I ran the time tests as I always have in the past. One minute a screen exposed properly without any indication of underexposure, the next it was a disaster both in being underexposed and then overexposed. My thought surrounding the inconsistency and suspecting the shelf life nearing the end is that maybe my supplier unknowingly shipped stock that was nearing the end of it's life. Unlike Kodak products that post a date expiration on items, I have not seen any date stamp. I know old product getting through happens unintentionally at times. 
Maybe the soy based ghost remover that I had used in the past caused the emulsion to lock up. I am very careful however in the process of cleaning my screens with plenty of pressurized rinse involved. The only thing I can do from this point is try to figure out what not to do next time, clean those locked up screens, move forward, get this job printed and get on with life. 
One more thought: the temperature in my studio is a bit chilly now ranging anywhere from 60 to 65 degrees as opposed to when I normally work (seasonal) mid summer with high temperature. I allowed extra drying time on the screens after coating and even placed a small heater gently blowing warm air onto the screens. Could this chill in the studio be a factor?


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## macmiller (Jul 23, 2007)

As long as it doesn't freeze, you should be good.


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## tpitman (Jul 30, 2007)

My experience with QX-1 has been nothing but good. I started using it because I wanted a single emulsion to use for shirts and solvent air dry inks for yard signs. It's always washed out quickly after exposure, and reclaimed very easily.
You might order a quart new and see if the problem goes away. Underexposure might mean your bulb is going, but halogen bulbs aren't the best to begin with, but if the problem comes and goes, it's something else.


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## RichardGreaves (Nov 7, 2006)

*Exposure fundamentals*

Jean, 

You're confused, but you have lots of information to stimulate diagnosis. 

I'm sure you meant "de-humidifier" in Post#1.
You don't actually say how your stencil is failing you.
You don't mention how you're testing/measuring exposure.
You don't mention what ink you need to resist.

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 the stencil breaks down - it's under exposed.

Exposure is at minimum, a combination of your positive, the stencil and the UV energy to cause a reaction with the sensitizer.

You're using a household worklight, laser positives and not measuring your exposure. That's OK, just harder to make judgments without examples. You've done a good job of hiding where you live, but you have to be buying Lawson SBQ-510 from Lawson. They can help you with this.

To monitor exposure, you should use a US$10 Stouffer T-2115 21 Step gray scale on every screen you expose for the rest of your life.
http://www.ulano.com/support/training.htm#21
Exposure FAQ Screen Making Products how to measure exposure

Shame on whoever sold you a stencil that doesn't change color without a way to measure exposure.

Once you know how to completely cure the stencil so it will survive developing and a print job - then you can focus on how to get fine lines to print. That's when you worry about using an exposure calculator.
*
Exposure is easy*
Exposure is easy - if it dissolves with water, UV energy didn't cure/harden it. The proof is in your screen.

If the image area is 'crusty' and doesn't dissolve, it usually means *your positive failed* to stop invisible UV energy from reaching the image area like a bad raincoat or the image area is closing up because of *light scatter & undercutting.
*
Light scatter & undercutting are how most people incorrectly describe over exposure.

*Positive comparison*
Next time you expose any screen, test if your positive completely stops UV energy. Tape a dime (any thin coin), or a piece of aluminum foil to the stencil.

No light will penetrate the dime and that area should wash out like a dream compared to your positive.

Laser toner is notorious for not being a good UV energy stopper, except for the Xante ScreenWriter that is designed to deposit more than usual deposit and has higher fuser temperature than average office lasers.

To work for screen printing, media has to be textured - that's why we use transparent paper with a *vellum finish* and polyester film must be textured.

http://www.t-shirtforums.com/screen-printing/t114546.html#post671670

*QX-1*
*QX-1* is a hybrid dual-cure that is pre-sensitized at the factory so there's no color change. You got resolution, not speed. QX-1 emulsion is no faster than any other dual-cure emulsion even though it's sensitized at the factory. You've made an almost identical choice with *Lawson SBQ-510*.

With your home-made *quartz halogen UV source*, you might consider a faster exposing emulsion like Ulano *QLT* - twice as fast.
*
Quartz Halogen
*A US$10 quartz halogen incandescent lamp emits at best 3-5% invisible UV-A energy. All that lovely bright visible light and invisible 1,000F infrared heat are wasted. Beware of the eye protecting safety glass if you haven't removed it. Coatings on SOME lamps and the safety glass, filter UV rays to protect your eyes and living room curtains from damage.
You won't find a 500 watt quartz halogen lamp on stencil data sheets is because there are no industrial standard for the hundreds of consumer household lamps intended for use as visible light, many have a UV filtering coating.

We are seduced when we see 500 watts, but that's electricity in, not the UV-A energy we need - out! Lots of wattage in the wrong light spectrum is useless.

*
Batch Codes*
All the stencil materials will have a lot number and the manufacturer can tell you the age.

Ulano internal batch codes are on the label. They start with 2 letters followed by numbers. The first letter is code for the year. 2009 = R. The second letter is the month, A-M January thru December. If your container batch code starts with a letter less than R, you have out of date emulsion.


*Stencil Removal/Reclaim Mesh*
When you expose your stencil, UV energy reacts with sensitizer and *joins *- causes a chemical cross-link between the two components that make up the "emulsion". Linked together, and woven in and out of your mesh, the exposed stencil will not dissolve with water (insoluble), and rinse down the drain. What doesn't dissolve is ready for printing when it dries.

Stencil remover attacks these cross-links, releasing the stencil so it can again dissolve with water and rinse down the drain.
*
Under exposed stencils are harder to reclaim*
Exposure is the only action you have where you control how the stencil will behave. Fully, or even over exposed screens, (contrary to popular belief), actually reclaim easier than under exposed screens. They also leave less diazo ghost haze images, don't break down on press, and result in far fewer pinholes.

*Shop Temperature*
Your shop temperature won't effect the emulsion.

*Reclaim Homework*
http://www.t-shirtforums.com/screen-printing/t116040.html#post681418


Richard Greaves (search for RichardGreaves)
_Supply Director for Lawson 2000-2005_


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