# Speedball Diazo emulsion (advice)



## pieface (May 21, 2009)

Hi again everyone,

just thought I'd mention a few things. I'm using speedball diazo kit emulsion and a lot of people have said it's only really good for the hobbyist, but I am surprised at its capabilities.

PRO: i think (not 100% sure) that i have a 43T screen and I'm quite surprised and happy with the results I got during todays exposure. some clean crisp lines and going down to some fine details. (this was a test and I did mess up a couple of things... i think the frame has warped due to bein washed so many times). 

hand drawn image printed by inkjet onto OHP sheet:
[media]http://www.fileden.com/files/2007/2/4/734740/screen%20prints.jpg[/media]
CON: I dont know if its just the environment in which i let the screen dry (dusty?) but i get a lot of what look like lighter trapped bubble areas once its dry... this then causes a few problems when trying to wash out the stencil.. bits get removed that i need! 

green circled area for example:
[media]http://www.fileden.com/files/2007/2/4/734740/stencil%201.jpg[/media]
but also I tried peoples advice from here of using an exposure time of 6-8 mins on the emulsion... OMG! was it annoying... took 3 attempts to wash out.. WITH a pressure washer! that also ruined parts of my stencil 

anyway... does anyone have any advice for the bubbles thing? and i think im gonan revert back to my 4 min exposure time that my step test produced.


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## Solmu (Aug 15, 2005)

If I had to guess:

Red circles: contaminants (like dust) or lumps in your emulsion that are getting transferred to the screen.

Green circle: Moisture falling on the screen while it's drying causing runs, *or* screen wasn't fully dry when it was exposed.

Blue circle: Positive not opaque enough, so light is coming through. Would otherwise have been a good exposure.


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## pieface (May 21, 2009)

Solmu said:


> If I had to guess:
> 
> Red circles: contaminants (like dust) or lumps in your emulsion that are getting transferred to the screen.
> 
> ...


Thankyou very much Solmu,

I lock my screen in a pitch black room, so i guess that explains the dust... but the green circle/moisture i just dont understand... i let it dry horizontally but do i need to have some sort of cover/shelf over it?

thanks


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## Solmu (Aug 15, 2005)

pieface said:


> the green circle/moisture i just dont understand... i let it dry horizontally but do i need to have some sort of cover/shelf over it?


Depending on the humidity of the room, how long you let it dry for, etc. it might not be fully dry when you expose the screen. A dehumidifier would help, _if_ that's the problem. I might not be right about what the problem is though - it is just my guess. While I am a printer, I'm certainly no expert on emulsion.

From here it just looks like the last bits of the screen to dry look like on my screens.

Maybe it's run-off from parts of the screen being underexposed though. Maybe it's thick spots from an uneven coating of emulsion. Maybe it's something entirely different I haven't considered. Sorry I can't be definitive.

But yeah, if you're looking for one thing to try/eliminate: keep moisture down, and give ample time to dry.


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## pieface (May 21, 2009)

thanks again... I dont think it's a problem with drying... I ended up leavin this screen for over 8 hours to dry (at least!)...

i dont use a coating trough at the moment, i just squeege the emulsion on, coating both sides and making sure there are no think clumps or runs... but ARGH.. its just annoying  after coating i let it dry but in that time it appears on my screen before exposure... 

as im coating the screen everything appears normal... that kinda makes me worry that its my emulsion now! but i have no idea what ive done if thats the case.. 

thanks Sol/Lewis


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