# expose time



## overthecurve (May 18, 2007)

I expose my screen for around 1 hour with a 150 halogen watt light. And i started to hose it outside (was dark and used a light to see what i was doing) it was starting to work and then it just wouldng come out. After trying it for about 5-7 min i gave up and then i was washing it off with just warm water since i didnt get my remover yet, then the mould was starting to show but then just went away for good.

How long should my expose time be with a 150 halogen light.

The height is about 17inch away from the screen..

Can someone help me out.. 

Also is there any other stuff aroudn to house to clean the emulsion on the screen, just incase my stuff doesnt come in by tommorow.


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## tynie626 (May 2, 2007)

well i used a 150 flourescent bulb before with a 10x18 screen, at 12 inches for 45 minutes, with speedball emulsion and all was fine.. now im using ulano qtx, with a 250 watt halogen work lamp at 18 inches with a 18x18 screen at 18 inches and it takes me about 25 minutes..

also when i wash out after exposing, i use cold water


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## mizi117 (Mar 12, 2007)

why so long?I used 150 halogen bulb and only takes about 10 minutes to expose the emulsion.But the height is about 6 inch.


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## tynie626 (May 2, 2007)

mizi117 said:


> why so long?I used 150 halogen bulb and only takes about 10 minutes to expose the emulsion.But the height is about 6 inch.


6 inches seems very close to me!! at the 18 inches i use, the glass on top of my transparency is burning up! i wouldn't want to risk burning my screen!!


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## mizi117 (Mar 12, 2007)

its up to you.I just tell what i've experienced.


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## RichardGreaves (Nov 7, 2006)

overthecurve said:


> I expose my screen for around 1 hour with a 150 halogen watt light. And i started to hose it outside (was dark and used a light to see what i was doing) it was starting to work and then it just wouldng come out. After trying it for about 5-7 min i gave up and then i was washing it off with just warm water since i didnt get my remover yet, then the mould was starting to show but then just went away for good.
> 
> How long should my expose time be with a 150 halogen light.
> 
> The height is about 17inch away from the screen..


If the stencil doesn't wash out, it was crosslinked somehow - either UV light, stray light in your shop or too much heat (110F+) for several days.

Your positive may have failed and light got through it. Next time you expose, tape a dime to an unused area of the stencil as a proof. No light will penetrate the dime and it should wash out like a dream. If your image area doesn't wash out the same way, your positive is weak.

You can do better than 150 watt halogen lamps even on a small budget. Big box hardware stores have 500 and 1000 watt quartz halogen work lights, but they get very hot - watch out. Remember, even though you may be putting 500 waats into the lamp, most of it is generating heat and white light for reading or working - NOT UV. UV is just a handy byproduct for us. 

Remember to remove the protective glass. It's there to stop UV light from damaging your eyes.

Learn to make a step test to determine exposure time.
http://www.ulano.com/video/UlanoExposureTest.256k.wmv

Use a fast exposing SBQ emulsion to compensate for your low UV light source.


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