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Discussion Starter · #1 ·
Hi all,

This is the first thread I have ever written and I very much appreciate anybody willing to help me out here.

I bought an exposure unit on Craigslist. It is an AWT- It is old- manufactured in 2006. I attached a picture of the unit and the lightbulbs in it.

Prior to this, I was just using that little tiny box from Ryonet.

Anyways, I tried exposing screens last night, and failed miserably. The screens all came out so underexposed that the emulsion just rinsed off.

I tried 4 minutes for the one screen with dual cure on it. And then I tried 3 minutes for Photopolymer screens.

My times on the little box from ryonet were similar.

I am so confused, shouldn’t this big vacuum unit with 8 bulbs expose faster than the crappy two light bulb box from Ryonet.

Are these lightbulbs the right kind?? I know T12’s are being discontinued but are these the wrong T12s?

Honestly, I had no problems using the little box from Ryonet and my screens always came out looking pretty good. The reason I bought this new unit is because I want to be able to expose the whole screen and this allows me to do so.
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Discussion Starter · #3 ·
Can you ask the person you bought it from what their exposure times were ?
I would but the person who owned the shop passed away and it was the property owner selling the equipment. They did have two exposure units though- I couldnt tell you if they were even using this one. I am thinking maybe these light bulbs arent black light? I dont think cool white are the right ones exposing but I have no clue.

But I am confident that my exposure times on this big industrial unit should be better than the little crap box from Ryonet.

And before anyone says it- I degreased and dehazed and used the same Hybrid Emulsion and Photopolymer Emulsion that I normally used.

Again, the screens were so underexposed that the emulsion just washed away

Thank you for your reply.
 

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Discussion Starter · #5 ·
Thank you but AWT no longer sells T12 bulbs so this does not work. T12s have been discontinued. I found some on ebay that look to be right F20T12/BL but they are listed as Bug Zappers. so I am skeptical if this is right.
 

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That tube that says "Cool White" is just a normal office light tube, no UV at all.

Options:

- Find some actual UV tubes for sale somewhere. UV tubes are used in "bug zappers" because UV light attracts bugs, not sure is the spectrum is 100% on target for exposing screens, as they might be more like Black Lights used for trippy posters and hip bars. You want the kind of UV tube that does NOT look purple/black when turned off, but more whitish. I used to buy at 1000bulbs.com

- There are LED replacement "tubes" but I don't know if anyone is making those in UV (normal lighting LEDs emitting zero UV, so only those purpose made to emit UV do so).

- Scrap the tubes and holders and ballasts, and retrofit it with UV LED strips and drivers.
 

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Discussion Starter · #7 ·
That tube that says "Cool White" is just a normal office light tube, no UV at all.

Options:

- Find some actual UV tubes for sale somewhere. UV tubes are used in "bug zappers" because UV light attracts bugs, not sure is the spectrum is 100% on target for exposing screens, as they might be more like Black Lights used for trippy posters and hip bars. You want the kind of UV tube that does NOT look purple/black when turned off, but more whitish. I used to buy at 1000bulbs.com

- There are LED replacement "tubes" but I don't know if anyone is making those in UV (normal lighting LEDs emitting zero UV, so only those purpose made to emit UV do so).

- Scrap the tubes and holders and ballasts, and retrofit it with UV LED strips and drivers.
This is spot on my friend. I spend my whole day trying to find these things and I was finally just successful. Sharing the link as I am sure it will be useful to someone with an older unit because these bulbs are kinda rare. Especially the unfiltered ones.

After calling all day- I found these guys- Satco S2925 F20T12/350BL/ECO - 20W - T12 - G13 Base - 24 .. They knew exactly what I was looking for and said screen printers call all of the time looking for them. Apparently they can take a 1 or 2 weeks to come in but they are in the process of getting a new supplier in the next couple of days. They are the unfiltered T12 UV Black Light Bulb PLUG!

I might take your advice and scrap the tubes and ballasts and get some LEDs in there but I am certainly no electrician so this will take some time. Any sources you could recommend for me to learn how to do all of that?
 
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