Old Exposure unit times?

[mimosatexas]

I know you love the HVP Alan, and I use it for my thicker low mesh stencils and LOVE it for those, but man o man is the SP1400 holding better detail on my 1k MH unit.  I can expose the SP1400 for basically whatever I want and hold every dot on a 55lpi screen, but if I go over even 10 seconds with my HVP i start getting major undercutting and lose 5-10% on the low end, so I have that dialed in for basically every mesh and coating method as a necessity.  The SP1400 I basically just do 2/1 sharp on every screen and expose for the same amount and they always come out perfect.  Takes about twice as long though...

[Inkworks]

Those are pretty amazing burn times.  If a bulb will last that long and you can get those burn times there would never be a reason for you to think about LED. 

I thought so. No doubt it's because the bulb is so close to the screen. It takes a few hours to retro-fit in a neoprene blanket, but once that's done it's a great unit.

I think the bulb last so long because it's only on during the burn, no shutter.

tough to beat when you can pick up one for the price of a new integrator:

http://www.ebay.com/itm/Nuarc-Plate-Maker-FT26V-/251584831350?pt=LH_DefaultDomain_0&hash=item3a939fdf76
(this unit will only do a 20x24, you need a FT40***** for 23 x 31" screens)

[ABuffington]

Exposure latitude is something that gets overlooked when we are talking about fast exposures.  Take 20 seconds as an example.  If you are able to expose that fast on your unit there is no room for error.  1 second either way is 1/20 = 5% for each unit.  Thats a lot of difference in exposure.  Does the Starlight allow you to shoot in tenths of a second? 

[sqslabs]

Exposure latitude is something that gets overlooked when we are talking about fast exposures.  Take 20 seconds as an example.  If you are able to expose that fast on your unit there is no room for error.  1 second either way is 1/20 = 5% for each unit.  Thats a lot of difference in exposure.  Does the Starlight allow you to shoot in tenths of a second?

Mind blown...  Thank you sir. 

[Shanarchy]

Exposure latitude is something that gets overlooked when we are talking about fast exposures.  Take 20 seconds as an example.  If you are able to expose that fast on your unit there is no room for error.  1 second either way is 1/20 = 5% for each unit.  Thats a lot of difference in exposure.  Does the Starlight allow you to shoot in tenths of a second?

This was another thought of mine with going to LED. I burn a screen is 85 seconds (actually 85 LTU). I can burn that same screen in 75 and still wash it out. If my new burn time with an LED becomes 20 seconds, then I would probably only have a 2 second forgiveness time.

All in all it would probably be fine, you just have to make sure you are 100% dialed in with your exposure times. Which we all should be. I guess it leaves a little less room to be lazy.

Good question on weather or not they can shoot in tenths of a second. I have a feeling they do. I've hear some emulsion having a 3 second burn time, so those tenths of a second sound like they could be pretty critical.

All this decreased exposure talk make me question waterproof film (again). I have complained about this for a while. WP film takes 10 seconds longer for me to expose. I can't be the only one who gets longer exposure time when using WP, but it seems like that is just what everyone uses. I can also hold better halftones on NON-WP. I know the big guys are going CTS and avoiding film all together. And I'm way too small of a shop for those 10 seconds to really matter, but I never seem to hear anyone else complain about that issue.

[Squeegie]

NuArc 3140
Running an OLD bulb...almost 3 years...yikes!

137  coated 2/2 - 50 LTU
156  coated 2/2 - 40 LTU
175  coated 1/1 - 30 LTU
195  coated 1/1 - 25 LTU
230  coated 1/1 - 20 LTU
305  coated 1/1 - 15 LTU

All yellow mesh.
Sharp edge of coater.
QTX emulsion

[bulldog]

Just thought I'd throw in my observation so far with the LED (Starlight.) I'm still dialing in my times and need to run a lot more tests but when I first burned a screen with 110 white mesh, coated 2 (sharp) / 2 (dull) with some hifi blue I tried 30 seconds. I could tell it was overexposed but I could still wash it out without much trouble. So the next screen I tried was identical but I did 20 seconds. It washed out much easier but still somewhat overexposed. These were waterproof film...just simple art, no halftones. My point is I was able to wash out both screens with no problem but the one had a 50% greater time.

I have a KIWO Expo Check that I'm going to use to do a lot more tests hopefully next weekend. I'm going to try and build a chart with different meshes and using Ulano Orange, Aquasol HVP and the Hifi Blue and see what happens. (I'll post the results in a different thread.)

[jvanick]

I've noticed the same results in regard to over exposure ... on the led units it just doesn't make that big of a difference if you're over...

[ABuffington]

One comment about Metal Halide Bulbs: Toward the end of their life they will still make a plastisol screen, but they will not expose a WB/Discharge screen well.  They will image, but the emulsion will not have the same water resistancy as when shot with a fresh bulb.

Alan

[IntegrityShirts]

I know you love the HVP Alan, and I use it for my thicker low mesh stencils and LOVE it for those, but man o man is the SP1400 holding better detail on my 1k MH unit.  I can expose the SP1400 for basically whatever I want and hold every dot on a 55lpi screen, but if I go over even 10 seconds with my HVP i start getting major undercutting and lose 5-10% on the low end, so I have that dialed in for basically every mesh and coating method as a necessity.  The SP1400 I basically just do 2/1 sharp on every screen and expose for the same amount and they always come out perfect.  Takes about twice as long though...

In my experience, reclaim also takes longer with SP1400. HVP is super quick to shoot and reclaim. But I agree, SP1400 holds better detail. It is still my belief, and it could all be in my head, that HV blue emulsion holds better detail than the pink. In my mind light "glows" around in the pink emulsion partially exposing it whereas the darker blue doesn't allow the light to scatter as much. Abuffington, am I right or crazy?

[3Deep]

the emulsion I found that really held detail on a crappy flo tube unit which I had at one time was Image Mate 521 dual cure using yellow mesh.  Guess know one on the forum here us it since it's never mention or talked about except for me.

darryl

[alan802]

Just got a gallon of the 1400.  I should have some screens coated by the end of the day.  So what would everyone say as far as burn times up against the HVP?  If I can do a 150/48 HVP screen with 4 LU's, where would be a good place to start with the 1400?

[Prosperi-Tees]

On my crappy flouro unit I expose the 1400 between 5-8 minutes. It is killing me in time and it is tougher to reclaim but I like that its $34 a gallon. If I can find a pure photopolymer that has wide exposure lattitude I would be happy. Sometimes I will forget a screen is in the unit and overexpose which with the 1400 really makes no difference. I know with a pure photo polymer if I forget it I will be starting over. I guess I need to start using the timer lol!

[IntegrityShirts]

Just got a gallon of the 1400.  I should have some screens coated by the end of the day.  So what would everyone say as far as burn times up against the HVP?  If I can do a 150/48 HVP screen with 4 LU's, where would be a good place to start with the 1400?

I'd probably start with 80LU with an exposure calculator. If we're taking bets, my guess is 38.2354LU!

[alan802]

I can't be the only one that has great exposure latitude with the HVP.  Jameson, your issues with latitude on the HVP were they really bad or just barely noticeable?  Maybe the light source plays a much larger role in latitude than I think and just because I can do a 305 for 6 seconds or 6 minutes doesn't mean everyone can.