# HELP with Speed-ball exposure times pretty please!!!!!!



## IncT (Dec 15, 2009)

IncT T-shirts's Photos - Wall Photos | Facebook
Hi there gang, I'm looking to get some help on exposure times. I just got a new batch of Speed-ball Emulsion (Blue) and am about to coat my screens. I have a UV light-box with 6x15w UV tubes that sit 7cm from the glass. Does anyone know how I can calculate the time needed to expose my screens. Thanks for your help and time.

Ben


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## DogPound71 (Jul 7, 2009)

I like the light box. Did you by or make it.?Try and use a piece of card board and use it as a step timer. Use a sreen and expose it a step at a time with the card board and expose the c b 30 sec at a time to see how long of a exposure you may need to get a good exposure.
I hope this will help, sometimes it hard to get replies from folks.


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## IncT (Dec 15, 2009)

Hi there, I was lucky enough to be given the light box, but I also have some plans on putting one together (just dimensions etc). IncT T-shirts's Photos - Wall Photos | Facebook
My only prob is that I don't have enough screens and time to test the exposure. Is there some other way I can calculate the exposure time? Most that I've seen have been for 500w halogens and so on. Hmmm this hurts my head!


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## BroJames (Jul 8, 2008)

IncT said:


> IncT T-shirts's Photos - Wall Photos | Facebook
> Hi there gang, I'm looking to get some help on exposure times. I just got a new batch of Speed-ball Emulsion (Blue) and am about to coat my screens. I have a UV light-box with 6x15w UV tubes that sit 7cm from the glass. Does anyone know how I can calculate the time needed to expose my screens. Thanks for your help and time.
> 
> Ben


I am not familiar with your emulsion but a 6x15w UV fluorescent unit with glass 7cm off the tubes should expose most emulsions just under 1 minute to about 1:30 min. You should find time to step-test the proper exposure time.


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## IncT (Dec 15, 2009)

BroJames said:


> I am not familiar with your emulsion but a 6x15w UV fluorescent unit with glass 7cm off the tubes should expose most emulsions just under 1 minute to about 1:30 min. You should find time to step-test the proper exposure time.


Thanks for your input, the help is appreciated. When I get a chance I will do a proper test. I was hoping there would be a program or something where one can fill out their details etc and be given an exposure time. Thanks again!

Ben


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## IncT (Dec 15, 2009)

BroJames said:


> I am not familiar with your emulsion











The emulsion I'm using!


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## station22designs (Dec 28, 2009)

I expose for 8 minutes with my black light bulbs. But I would strongly suggest using the exposure calculator. We dialed our in in 2 screens. Best investment in time we ever did.


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## IncT (Dec 15, 2009)

station22designs said:


> I expose for 8 minutes with my black light bulbs. But I would strongly suggest using the exposure calculator. We dialed our in in 2 screens. Best investment in time we ever did.


Ok, I did two test this one is at 8mins with 6x15w BL bulbs...http://www.facebook.com/pages/IncT-T-shirts/235373156168#!/photo.php?pid=4189673&id=235373156168 no joy! I then did another at 5mins...still no joy! Just doesn't seem to want to stick to the screen. Time to scratch my head!


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## station22designs (Dec 28, 2009)

What we did is number a transparency in 0.5 minute increments( 1-20). We then used strips of poster board to cover each area. We started exposing the screen and removed the stips starting at the higest number and removed another strip every 30 secs. Once completed we washed the screen. Part will totallly was out. What we look for is the sharpest numbers from the strup test. The first test will get you into the right range. a second one will help zero it in. Your emulsion is very forgiving so if you get with in a minute you should be fine.


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## BroJames (Jul 8, 2008)

station22designs said:


> I expose for 8 minutes with my black light bulbs. But I would strongly suggest using the exposure calculator. We dialed our in in 2 screens. Best investment in time we ever did.


Are you sure you are using BLB UV lights? What is the distance of your glass (to bulb)?

Using a (borrowed) 4x20w regular household fluorescent unit at a height of 12" I expose screens in 12-15 minutes. Others reported that at 6-7" distance, exposure is 6-7 minutes(I think); at 3" glass to bulb distance exposure is 5-6 minutes.

At 3" height using BLB, it seems unlikely for the exposure time to take any longer than using regular household fluourescent bulbs.

At 6-7" using white 4x20w white UV fluorescent bulbs exposure is around 2 minutes; At 3" exposure it takes just about 1 minute to expose.

From what I gather, the different brand or type of emulsion used here requires little or no adjustment in exposure time.



IncT said:


> Ok, I did two test this one is at 8mins with 6x15w BL bulbs...http://www.facebook.com/pages/IncT-T-shirts/235373156168#!/photo.php?pid=4189673&id=235373156168 no joy! I then did another at 5mins...still no joy! Just doesn't seem to want to stick to the screen. Time to scratch my head!


Are your emulsions washed out after 5 minutes? As posted, you are using BLB fluorescent tubes (or is it BL) set at 7cm distance below glass right? If so, did you degrease your screens and rinse carefully? The problem does not seem to lie with your exposure unit. Have you contacted your supplier regarding this problem?


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## BroJames (Jul 8, 2008)

IncT said:


> Ok, I did two test this one is at 8mins with 6x15w BL bulbs...http://www.facebook.com/pages/IncT-T-shirts/235373156168#!/photo.php?pid=4189673&id=235373156168 no joy! I then did another at 5mins...still no joy! Just doesn't seem to want to stick to the screen. Time to scratch my head!


Are you using BLB fluorescent tubes set at 7cm distance below glass right as posted earlier or are they BL which seems to be the case in your linked pictures (below)? 








The problem does not seem to lie with your exposure unit(above) which should expose most emulsions in 50 to 180 seconds. The problem also seems to be localized in some areas(below). 








Did you degrease your screens and rinse them properly?
How do you wash off the exposed screen? What are those dark areas in the emulsion in the right side of the picture?

A guess would be insufficient degreasing, overexposure and a strong water pressure to wash off the overexposed areas.


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## IncT (Dec 15, 2009)

Hi there, I think that might be the problem. The degreasing. Normally if a screen fails I apply "fotocoat 2005 emulsion remover" to clean the screen off. Hose that down and allow to dry flat, I barely touch the screens with my hands. If needed I'll use a haze remover to get rid of any unwanted ink etc. Again I allow that to dry flat. Is this the point where I should be degreasing my screen? To be honest I've never done that. Most screens I get I remove them from there plastic wrapper (if they come in one) and coat straight away, It was only recently when I switched to _Murakami photocure TXR _emulsion when I noticed all this happening. I thought I had a bad batch of emulsion and switched it for this other "speedball" one. Anyway, I do think it might be the fact that I haven't degreased them after reclaiming my screens. Also, those darker areas is just me being untidy when coating my screen.


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## BroJames (Jul 8, 2008)

With Murakami Photocure TXR as the point of reference, 8 minutes exposure time on a 6x15w UV fluorescent set 7cm below the glass is definitely overexposure (unless Murakami shipped a different mix of TXR to the US). I've exposed murakami TXR 12" above 4x20w household fluorescent in just 12-15 minutes(1-4 coatings). In relation to your UV unit, I would expect exposure in just 1 minute. Start your step test at 40 seconds.


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