# Questions about exposing screens



## Bayarearich (Feb 3, 2019)

Hi I am new to screen printing and I’m having issues burning screens I have a exposure unit with vacuum it has six four foot Florissant bulbs in it that are 25w ea. I’ve tried 3 different times now was the first time I’ve burned for 3 1/2 minutes and my image kind of came out but washed a lot of it out the second time I went for 55sec and nothing washed out So I’m trying to figure out how long should I be exposing the screens for Thanks in advance any help is appreciated


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## hawaiianphatboy (Apr 28, 2008)

It is odd that nothing would of washed out at 55sec, but would wash out at 3.5 minutes and still wash out a little bit. if it was washing out a little at 3.5 minutes, you should try 4 minutes. Also double check the emulsion you are using, is it a two part emulsion or a pre-mixed one. If it is a two part emulsion, did you mix the emulsion. Also double check the ink that you are using to print your positives. Are you using UV resistant ink that will block out the necessary UV light to protect and burn your image properly. Good Luck.. Aloha


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## Bayarearich (Feb 3, 2019)

Sorry I was wrong so 55sec it Completely washed out in a minute and 45 seconds image was a little better add four minutes I couldn’t wash any out


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## LancerFlorida (Mar 20, 2018)

The quick answer is to obtain a exposure strip to help you dial in your times. Ryonet offers one and another is offered free if you search big G.
Having an exposure strip on hand is a really great idea and essential should you change emulsions, coating process, film creation, alter exposure system.
Otherwise, consider doing an exposure step test using one screen with a mask to step through 30 second time intervals.
Make it a practice to repeat the test monthly to make sure your operation isn't drifting into trouble.


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## sandhopper2 (Apr 26, 2010)

LancerFlorida said:


> The quick answer is to obtain a exposure strip to help you dial in your times. Ryonet offers one and another is offered free if you search big G.
> Having an exposure strip on hand is a really great idea and essential should you change emulsions, coating process, film creation, alter exposure system.
> Otherwise, consider doing an exposure step test using one screen with a mask to step through 30 second time intervals.
> Make it a practice to repeat the test monthly to make sure your operation isn't drifting into trouble.



Can you show how to do the mask at 30 second intervals , some pictures would do great for me


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## Bayarearich (Feb 3, 2019)

Question what emulsion are you guys using I’m starting to think that might my issue. My emulsion might not be any good I’m useing the ulano otx ultra fast dry textile emulsion But will change to whatever you guys suggest


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## hawaiianphatboy (Apr 28, 2008)

I use the Ulano QTX, it is pink in color. I normally expose my films for about 2.5-3 minutes i believe, and they come out fine. Even when doing halftones. I was going to say, normally if you underexpose you will get a complete wash out or at least some. if you slightly overexpose, you may still be able to get it to wash out, it just may take more time. When I expose my screens, since i dont have a washout room in my garage, I will remove the films from the screen and rub both sides of the screen with water using a sponge. I will make sure that i cover the image are with water and will rub it a little extra to loosen up the emulsion a little bit. I will then let the screen sit for a few minutes, in the light safe area, and let the water soak in and break down the emulsion. After a few minutes I will take my screens outside and wash them with your garden variety garden hose attachment until the image comes out. If have a few small areas that do not come out completely i will again rub the sponge over the image area to clean it out. If i have overexposed it a little, rubbing the screens with the sponge before and after a little longer will normally salvage the screen. Aloha


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## Bayarearich (Feb 3, 2019)

Can I ask what you are using for an exposure unit?


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## NoXid (Apr 4, 2011)

As suggested, do a Step Test. See the link in my sig. You can get your time dialed in with just one screen, two max. It is a frustrating waste of time and energy to waste an entire screen on one guess. Test!


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## Bayarearich (Feb 3, 2019)

Got it figured out tonight wasn’t exposing my screens long enough thanks for all the help guys


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## danlewerenz (Apr 27, 2009)

Dont use the pink textile emulsion. Use the Graphic Hu from Saati print. Burn for 3 min. Walla!


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