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Discussion Starter · #1 ·
I've been using a homemade unfiltered blacklight exposure unit with a vacuum blanket for years now, but just finished a job (simulated process on black shirts) that I had a tough time with the darker toned areas - say above 75%. Additionally, doing any kind of gradient oftentimes results in a rather abrupt cutoff on the lighter end. At any rate, I'm considering purchasing a commercially made metal halide exposure system to maximize screen quality regarding halftone reproduction, and have narrowed it down to either NuArc's 3140 or Amergraph's AdVantage 150. The specifications for both are almost identical, but the NuArc is considerably more expensive. I'd appreciate any comments, both positive or negative, from owners or users of these two units. While there are plenty of workarounds to buying a commercially made unit, it's interesting that it seems as though everyone who buys one says they can't believe they got along for so long without one, and that it's one of the best investments they've made.
 

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Abrupt cutoff means you should calibrate to defeat Mother Nature as the diffused light energy cuts in from each side of the positive, choking the dots.

Make a test pattern of 2% 5% 10% 15% etc. dots also 99 through 75 and print a positive.

More percentages, the better the test.

Now you print the pattern on fabric.

Now compare with a magnifier. You now know if you choose 15% dots and they print as 9% dots, you can re-target, re-aim and calibrate so you get the dots you want.
 

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Discussion Starter · #3 ·
Thanks for the reply. I usually fiddle with the transfer function in Photoshop if outputting from there, but Illustrator doesn' t have that feature.

Regarding the exposure unit, I'd also like to go back to using dual-cure emulsions to gain resolution without waiting forever for a screen to burn.
 

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Tom, I'm sure you've seen my posts about exposures. I have had great success for years with a diy unit. I firmly believe the key is the light source and vacuum. I burn screens in less time than I've ever heard anyone on this forum quote. And all with excellent detail, durability, and resolution- escpecially with dual-cure.

I know the Msp 3140 is an excellent unit, so I'm not saying not to get one, but I have a friend that has a 4000.00 unit, and my screens come out the same or better in 1/3 the time. Get a metal-halide light source and you'll jump light years ahead in the burn game.
 

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I agree with Ridgely,

I made my 1000w MH unit with a vacuum top for less than $400 and it burns beautiful screens. The key is, like Richard said, dialing in your exposure times.
 

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Discussion Starter · #6 ·
I agree with Ridgely,

I made my 1000w MH unit with a vacuum top for less than $400 and it burns beautiful screens. The key is, like Richard said, dialing in your exposure times.
Philip,

Are you using the standard metal halide bulbs available everywhere?

Thanks,

Tom
 

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Discussion Starter · #7 ·
The transfer function is a postscript function, photoshop just happens to make it especially easy to use. For programs other than photoshop, the printers .ppd file can be edited with the same numbers as the ones used in photoshop to yield the same results.

fred
Man, it's been a few years since I dug into a ppd to change line screens and so on to get what I wanted out of illustrator, but I never went into it to adjust the percentages on the low and high end of the grayscale. Used to have to do it to get the output I wanted from my laserwriter for reporduction on paper offset printing plates.

I'll have to revisit those wonderful moments from yesteryear.

Thanks,

Tom
 

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I agree with Ridgely,

I made my 1000w MH unit with a vacuum top for less than $400 and it burns beautiful screens. The key is, like Richard said, dialing in your exposure times.
Hi Neato. Have you posted on the forum somewhere the instructions to make your 1000w halide unit? Thanks, Liz
 

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can anybody post pics of the design/layout of their MH exposure unit please???? im in the beginning process' of making my own and would like to see others. thanks, can PM if necessary
 

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Discussion Starter · #11 ·
Well, I ended up buying the Amergraph 150 and while it's not as cheap as a home built unit, having a timer, a light integrator, a hot-strike bulb and a nicer vacuum blanket than the pond liner jobs I've been making for my blacklight units, not to mention the uptick in quality, I can't say I'm sorry I went this route. Getting my exposure times dialed in after switching to Ulano QX-1 has given me the best screens and halftones I've ever gotten. What I see on my monitor is what I get on my shirts.
 

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can anybody post pics of the design/layout of their MH exposure unit please???? im in the beginning process' of making my own and would like to see others. thanks, can PM if necessary
I am about complete with my exposure unit, I will post pics as soon as it is finished.
I am using a 1000w Metal Halide bulb and ballast I purchased from ballastkit.com for under $170.

I hope to have it completed this weekend, so look for pics very soon.

Cheers,

Tracy
 
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