# LED Exposure, what am I missing?



## FatPrints (Jan 8, 2019)

What's up guys? I am trying to dial in my LED Exposure unit with a couple different emulsions, on being the Cryocoat Green, and the other being Ulano Orange. My main struggle is holding fine detail on 230 yellow mesh with the Cryocoat. I'm using sharp side of the scoop coater, one pass on both sides (print side first, then squeegee side), drying completely, then exposing for 17 seconds. I can wash blocky prints and low detail out just fine, but when it comes to the fine stuff I find I'm blowing out the emulsion before the stencil actually gives. 

I'm really used to exposing with Halide, so this stuff is escaping me. any help or recommendations would be amazing. Thanks!


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## Gettingitdone (Apr 27, 2019)

Get out the Stouffer scale and see if you are getting a solid 7 if not where ever you end up with on the scale say a 5 then it's 17 sec multiplied by 1.444 x 1.444 = 35.444 sec rounded down to 35 sec. Each step is 1.444.


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## krikster (Aug 8, 2013)

Also try using a lower water pressure to wash your screens out to see if that helps you.


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## Gettingitdone (Apr 27, 2019)

I also should mention that I use Ulano Blue 2 x 2. First coat substrate side do a 180 and do the squeegee side then repeat substrate side a 180 and finish with squeegee side then into drying cabinet till totally dry. I also only use 110, 160 and 200 mesh screens with Union Aero inks and without Diazo for up to 100 shirts. Hope this helps.


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## gardenhillemb (Oct 29, 2015)

Sounds like you need to expose it for a few more seconds. Also, try washing it out with a bucket of clean water and a soft sponge. Don't scrub, just gently wash it until all the unexposed emulsion washed out. Power washers are rough on halftones.


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## FatPrints (Jan 8, 2019)

Thanks everyone, I appreciate the help! I figured out that I was using too much pressure, and exposing for about 6 seconds too long.


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## Gettingitdone (Apr 27, 2019)

All glass is not the same when it comes to exposures. I spent a good deal of time researching this out and I ended up with StarFire Low Iron Float 1/4" and my exposures are ultra fast. I also invested in a light integrator which was an expense but no do overs because the screen broke down. I built my own exposure unit and it's a flat bed with a secondary bed that fits inside the screen from the squeegee side with a hole in the centre for the photo cell that is right against the screen with the weight of the glass giving me excellent contact. The reasoning is reading the UV without a layer of emulsion is a false reading where as when the emulsion has totally absorbed the UV the lights go off. Now I set this all up with a Stouffer scale based on units of light to achieve a solid 7 with the photo cell outside the frame and then with the photocell under the emulsion and I find out the solid 7 is really more a solid 5 which proved to me that time only is a false reading or totally cured emulsion. Knowing each step is 1.444 I multiplied the units by 1.444 and exposed another screen. I was elated when the lights went out by the new number of units and the emulsion was totally cured through. Now if I have an off day when I coat screens too thick or too thin my exposure is still exact and my screens are solid.


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## krikster (Aug 8, 2013)

Gettingitdone said:


> I also invested in a light integrator





Do you mind sharing with us or me where you got that integrator?


And an image of how you set that thing up?


Thanks!


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## Gettingitdone (Apr 27, 2019)

It's a Douthitt Integrator and they have a website. The manual gives a general approximation of seconds to units so you have a starting point with a solid Stouffer 7. My exposure unit which I built is a waist high bench and a insert which fits into the squeegee side. I only use 16 x 20 screens so my aluminum frames are scribed with a centre mark along with the insert and the bed. This way all my light is centred to the screen and image and the lamp is overhead and centred to everything else. I took plastic pipe and made a curtain frame around the bed and a friend she made me a black wraparound curtain which shields the light from the lamp. If I figure out how to get a photo up here I will.


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