# Transparency film and photo emulsion question



## rmele09 (Jun 4, 2009)

I have a question regarding what to do with the transparency positive of my design during the screen printing positive. (I am new to screen printing) I place the design transparency onto the screen that has the dried photo emulsion applied to it, expose the screen, then do you keep the transparency on the screen while you apply the ink with the squeegee? I have watched videos and can't tell if the person has taken off the transparency or not. I also am having a problem figuring out if my screen has been exposed for long enough, I am using a 300 watt incandescent bulb, about 10 inches away from the screen, how long should this be taking? Is there a certain color the design should look when fully exposed? Thank you everybody for your time, I appreciate it.


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## Celtic (Feb 19, 2008)

rmele09 said:


> I have a question regarding what to do with the transparency positive of my design during the screen printing positive. (I am new to screen printing) I place the design transparency onto the screen that has the dried photo emulsion applied to it, expose the screen, then do you keep the transparency on the screen while you apply the ink with the squeegee? I have watched videos and can't tell if the person has taken off the transparency or not. I also am having a problem figuring out if my screen has been exposed for long enough, I am using a 300 watt incandescent bulb, about 10 inches away from the screen, how long should this be taking? Is there a certain color the design should look when fully exposed? Thank you everybody for your time, I appreciate it.


 
No. Immediately after you expose your screen (no idea how long it will take with a 300 watt bulb...you'll have to experiment...I'd suggest that you at least get a 500 watt halogen work light and use that ) anyway, immediately after you expose your screen, remove the film positive from your screen, then rinse the screen to release the image.
knock off excess water, then blot with newspaper and dry flat. 
I'd suggest that you get Ryonet's 'Screenprinting 101" DVD (silkscreeningsupplies.com) 
It has over 5hrs of step by step info....very good.


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## rmele09 (Jun 4, 2009)

Thanks I really appreciate the info. When you remove the transparency, is it supposed to be really sticky, or is it supposed to peel off smoothly? I tried for my first time and it sort of stuck to the screen and damaged the design, I don't know if its because I let it expose for too long or if the emulsion wasn't completely dry. As far as the incandescent 300 watt bulb, do you have even a close ball park figure of a timeframe? I know its tricky but I dont know if we are talking 5 mins or 40 mins what should I try do you think? Thanks again for the info its very helpful.


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## demtangs (Nov 21, 2008)

You probably need to let your films dry longer. If they are inkjet/ waterproof films they need some time to dry before printing. The emulsion may need more time too. 

As for exposure times, you really need to do an exposure step chart to correctly determine your time. Put something like a dark piece of paper over the emulsion and slide it off in equal time and distance increments until it is removed. Then, wash out the screen. The exposure times will be evident by the bands left on the screen. For 300 watt incandescent I would start at 10 min and move the card at 5 min intervals. But, it also depends on the age of the bulb and the distance from the screen. I also agree with Celtic, get something stronger. 

Most setups are unique so you'll just have to keep experimenting with yours. There are lots of great tutorials on youtube to get you started. 
Good luck!


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## MOYA (Feb 28, 2009)

Sounds like your emulsion wasn't completely dried if the transparency stuck to it during exposing. You should let a screen dry 3-5 hours, but that varies a lot depending on the enviromental conditions.
A 500 Watt halogen light would be a great addition to your supplies, though. If I had to guess how long it would take with a 300, I would say no less than 12 minutes. 

We wrote a short blog about exposure troubleshooting (and a few other topics), that you might find useful. 

I Troubleshot the Sheriff


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## PositiveDave (Dec 1, 2008)

I suspect the emulsion is still damp.
http://www.t-shirtforums.com/t-shirt-articles/t106506.html
http://www.t-shirtforums.com/t-shirt-articles/t108270.html


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## rmele09 (Jun 4, 2009)

Thanks for all of the great information, I really like that exposure test I am going to try that as soon as I get a chance. And the emulsion was definitely not dry, I only let it sit there for 30 mins lol. Thanks again everybody, I'll post back my progress.


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