# Screen printing: trouble getting straight lines after exposing/burning an emulsion coated screen.



## apebeast (Sep 10, 2014)

Original graohic:









Graphic after washing:









Wondering what I did wrong. 
Here are some notes:
- I coated the screen twice
- I exposed under direct 500 watt halogen light without glass for 11 minutes. 

Please let me know if there are some solutions to this.

Best, 
Apebeast


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## lvprinting (Sep 23, 2014)

We will need more info, plus it's hard to tell if your emulsion is good.

What mesh count is your screen? Was it properly washed and cleaned or is it a new screen?

How old is your emulsion and where is it stored?

How much weight was on the screen to hold the positive tightly to the screen?

Are you using a garden hose, sink, pressure washer, or something else to blow out the image on the screen?

Sent from my SM-G900T using T-Shirt Forums


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## BTCT (Oct 27, 2014)

looks like the film wasn't tight to the screen. You need some pressure to get crisp edges. I use 2 500 watt lights a piece of glass and a 2 1/2 inch foam square. And the emulsion could of not been all the way dry or over exposed. If the images takes longer than a minute or so and its hard to push out you can blow out your edges and detail. The image you burned should of washed out fast.


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## BTCT (Oct 27, 2014)

I would also recommend using the sharp edge of the scoop coater. a very thin coat of emulsion works best.


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## TYGERON (Apr 26, 2009)

A relatively "thin" coat of emulsion (as in fewer coatings) tends to allow subtle hills and valleys (space between threads and where threads overlap)across the screen that create inconsistent areas of exposure and a loss in edge definition. It's more pronounced with coarser mesh counts. I distinguish thin and number of coatings because a thin overall thickness can be achieve with multiple coatings. Thickness consistency is what's desired.

Do a search on effective screen coating, emulsion types, exposure etc.

And the photo looks like it may be a film/screen contact issue and light source distance amongst other things.


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## BTCT (Oct 27, 2014)

TYGERON said:


> A relatively "thin" coat of emulsion (as in fewer coatings) tends to allow subtle hills and valleys (space between threads and where threads overlap)across the screen that create inconsistent areas of exposure and a loss in edge definition. It's more pronounced with coarser mesh counts. I distinguish thin and number of coatings because a thin overall thickness can be achieve with multiple coatings. Thickness consistency is what's desired.
> 
> Do a search on effective screen coating, emulsion types, exposure etc.
> 
> And the photo looks like it may be a film/screen contact issue and light source distance amongst other things.


A thin coat works best for me and I have never had any problems with detail. A thick coat is really only for auto presses or getting a lot of ink on the shirt.


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## InkedApparel (Mar 18, 2009)

by the looks of your images....seems to be under exposed...but could also be over exposed, how long does it take to clear the image area when washing out? if it is relatively quick then I would say to add to your exposure time.

I know when I exposed using a 500 watt halogen it took a good 14 minutes to get a proper exposure.

-Inked


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## TYGERON (Apr 26, 2009)

BTCT said:


> A thin coat works best for me and I have never had any problems with detail. A thick coat is really only for auto presses or getting a lot of ink on the shirt.


 If a 'thin coat" works for you that's good to go.
Of course always go with what works for you. And when it comes to deciding what's "thin" or "thick" it's relative.

So to say 'thin-er' or 'thick-er' may be more apt.

A thin or thin-er coat alone more than likely won't eliminate the OP's issues.

A thick-er coat isn't really just for autos or heavier ink deposit. Beyond a single coat, additional coatings serve to even out the overall emulsion for a more consistent thickness which makes for a more even cure, improves edge definition, and lessens undercutting. A thick-er stencil also gives more latitude and control over how much ink is laid down particularly when considering other elements like squeegee durometer, angle, speed, pressure, ink viscosity etc. This applies to manual or auto printing.


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## BTCT (Oct 27, 2014)

I do a thin 1/1 when I mean thick 1/2 or a 2/2


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## StayG0LD (Jul 22, 2010)

This positive was not flat to the screen. Please use glass. Without force, even the slightest micrometer of lift will cause these errant gradations in exposure ESPECIALLY in the middle or the positive where the apex of any minimal screen frame warp lives (thus the preference for vaccum over down force, where there is no air, there is absolutely no space). Glass shop. Tempered w/ NO UV filtering please. 1/4 - 5/16" at least please. Thanks.


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