# exposure time 400w metal halide ?? step test



## 4taylormadetees (Jan 9, 2009)

i was wondering how to do a step test with a 400w metal halide?should i step up every 30 seconds or what? and do you need to warm up the light or just turn it on ?


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## 4taylormadetees (Jan 9, 2009)

70 views... alot of people must want to know how?


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## Bob Wellen (Jan 25, 2011)

I would make the step at a minute apart to make sure. You can always make a second shot after you view the results of the initial step test. Look on the Murakami web site. there is an article about howe to do a step test. www.murakamscreen.com


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## tabletop (Mar 1, 2011)

just got my table-line press bolted together . The 400w I had laying around is about to get hung for burning screens . Was looking for this info , thanks .


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## StampedTees (Jun 15, 2011)

Definitely start broad and work your way into smaller numbers .. If you're working with dual core emulsion naybe first test do 10 minute test in 1 or 2 minute increments. 2nd test do 10 or 20 second steps inside of the time that worked best on the last test..

If your working with fast emulsion just adjust the whole test accordingly.

Best of luck .. Coat 2 or 3 screens and take your time .. Accuracy with your step test will make your life easier down the road..


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## PositiveDave (Dec 1, 2008)

http://www.t-shirtforums.com/t-shirt-articles/t106506.html
I'd do it from cold because that's the way it will be used, if you find a great difference in a warmed up bulb you will need to factor that into your process.
Just do a very coarse screen first, 5,3 or 2 minutes apart, then you can do a second screen with fine intervals.
Bear in mind that your bulb will deteriorate over time so working it out to the exact second is a bit pointless especially if it has a warm up period.


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## rudi (Mar 7, 2007)

I Have a 400 watt M/H and we burn screens between 2 mins and 4 mins from cold. Distancewise (screen to light source) i measure from corner to corner (diagonally) my sreen and that determains the distance my light source will be.

Coating screens 1/1 (left printside down to dry in drying cabinet)

Good luck.


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## poker (May 27, 2009)

I have a 400+MH light facing up in an old cabinet. It takes me 4 to 4.15 minutes to burn a screen. I also use 1 and 1 coating. I do this for meshes between 125 to 230 (yellow).


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## threadbirdy (Dec 4, 2010)

I get my screens burned at a place round the corner and they do it in like 30sec with a 1000w metal halide bulb. For emergancies and back up I have a 125w uv bulb and it takes me 32mins lol. they burn really nice though, but the other weekend they were on holiday and for a 4 colour job it took me 2hrs just to burn the screens.....man gotta get me one of those metal halide bulbs.


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## latitude42 (Sep 26, 2007)

I built a MH exposure cabinet, does 20 x 24 screens, bulb is 18" from glass, no vacuum, I put a piece of black fabric on the backside of the screen after I lay it on the glass, pace a piece of 4" foam over the black fabric, then close the lid which is 3.5" and clamp the lid shut. The pressure of the foam onto the black cloth works great. I do halftones with no problem. 
Exposure time is 3min. 15sec. I use Ulano EasyFilm, bulb is 400wattMH, timer is done with a sliding shutter.
Whole thing cost me $100.00 to make and now I can do the fine detail stuff some of the big boys do, but I still have a manual press (6 x6).
Latitude 42


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## Zenergy (Apr 14, 2011)

Where are you guys getting your MH lights? The only place I can find locally is the hydro store, but they're expensive, like $300 for bulb, ballast, and reflector.


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## latitude42 (Sep 26, 2007)

Craigslist, $15.00, warehouse lights removed from a building, guy had 20 of them, I put a new bulb from Menards ($32.00), the old one was weak
Latitude42


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## punder (Mar 27, 2011)

My first 6 months I used the fool out of that 500 watt Halogen bulb . One day I had a tone that I really needed to figure out , I went thru lots of screens to figure out that it just was not going to work ( for me ) . I went to Home Depot and got a 100 watt MH ( Yea 100 watt ) , it instantly change everything . Great thing is if it is just not for you , return it . I now have a 400 Grow light off Craiglist that I am moving up to , and the info is great on here , it has really helped a lot , Thanks .


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