# ChromaBlue exposure time issues



## imrios (Aug 9, 2017)

Hi, Ive been screen printing for 3 years and have always used ChromaBlue emulsion, but lately i have been having trouble with my exposure times. I have a homemade exposure table with 32Watt fluorescent bulbs 2.5 inches below glass. I had my exposure times down to 10 minutes for the longest time, but now i have a hard time during washout, the emulsion is very gooey and blows out easily with the pressure washer. And if i try to wash it out without pressure i find myself trying to wash out for 30 minutes with no luck. Ive tried decreasing my exposure time to 7 and 5 minutes but same issue, then i went up to 12 and 14 minutes but not much improvement. 

I have been reading that unfiltered black light bulbs are the way to go, but maybe i can resolve this with what i got now.

I appreciate your help and suggestions.
Thank you


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## teesnow2017 (Jul 14, 2017)

Maybe your emulsion is too old/expired. Try with a new lot from your local supplier.


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## NoXid (Apr 4, 2011)

Well, given that this combination of unit and emulsion used to work fine for you, I would look at the two things that can and do change over time: 1) As tubes age, their output changes. It may be time for new tubes. 2) Old emulsion will fail to expose. Properly stored (cool), most poly/SBQ type emulsion should easily last a year. Check the date of manufacture on your container.


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## Rabbidsquirrel13 (Jul 27, 2015)

I would also check your printer to make sure that it is printing a pure black. If you hold your transparency up to the light can you see light coming through the black ink? 

It sounds to me like light is getting through the black ink of your transparency and semi-curing your image so that the image looks like it will spray out when you wash it down but the emulsion covered by your transparency is partially cured by the light.


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