# Problems using Speedball DIAZO Photo Emulsion (Fairly new to screenprinting)



## PlatypusClothing (Nov 19, 2013)

Hi everyone,
So I've been having problems from the start using Speedball emulsion where it will start to wash out in areas it's not supposed after the image is burned on no matter how long we seem to expose it for. (we have made test strips ranging from 2-18 minutes.) 

We coat the screen thinly on both sides with emulsion using a scoop, leave it overnight to dry in a dark space then do another coat the next night and repeat.

I have a full exposure unit with fluorescent blubs 
and it will be for use with water based inks (Permaset).

I am very frustrated but the lack of any progress, one screen had to be recycled so many times it's no good now and am running out of ideas of what to do next. I didn't think it should've need this much exposure time to begin with! 

Is something wrong with our emulsion? Should we try a different brand??

What exposure times do other people seem to get on well with?

Any advise would be a godsend right now! 
Thanks


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## Sulp (Dec 7, 2010)

Are u using it to print textiles? I'm not really familiar with speedball emulsion, but I don't think u need to coat a second time after it's dried overnight. Coat one time..once on the inside, once on outside, and then finish on the inside with one more pass. Sounds to me like a definite exposure problem, but if u know ur unit, and know how it exposes, then it must be something else. I use IMS 905 and have had no problems.


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## Omni (Mar 28, 2012)

Get a junk screen.....Coat it with emulsion (the same way you mentioned in your post)......Take it outside and expose it to sun for 5 minutes, without a film positive......1: watch to see if it changes color....2: take it in to wash......If it does not wash out, then the answer to your question is your exposure time with your unit, and you will have to increase your exposure time even more than 18 minutes, plus you will know that the emulsion is NOT the problem.......If it does not change color and still washes out, then either you don't have Diazo mixed in the emulsion or the emulsion is simply bad.......I also see you mentioning that you will be using water based inks.....When you do figure out your exposure problem, I recommend that after you wash and dry your successful screens, that you post expose them in sunlight after they have dried.....This will increase the screens resistance to water based ink......Personally, I would switch to another emulsion....I have found (for me) the best value ( surprisingly inexpensive for a great emulsion ) in Emulsion to be Murakami Photo Coat Pro.....a dual cure emulsion with excellent coating properties, wide exposure latitude, consistent from batch to batch, and excellent image quality, especially with weaker light sources......and lastly........Experiment.......it is the only way you will find the results that you are looking for.......


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## PlatypusClothing (Nov 19, 2013)

Thanks for the replies,
Slup: Yep for textile printing. I'm sure it's not a problem with the unit because when we first got it we tested it using a different emulsion (don't know what brand however, it was in a unmarked pot) and that worked fine. 

Omni: Good idea thanks, we will try exposing a screen in sunlight and see what the results may help us figure out the problem.
We mixed Diazo in according to instructions and store it in a fridge, so it shouldn't be anywhere near to expiring.

and for the cheers for the tip, will have a look into Murakami Photo Coat Pro.
We've also been looking at Olano QX-1, it's also a dual cure emulsion, anyone got any experience or heard good things about that?
I need to find out if it's okay to use with water based ink before purchasing anyway.


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