exposure time

[cleveprint]

anyone have a starlight and uses aquasol hvp? starting to mess around with some discharge and wanted to see if anyone had a good idea of for exposure times. for normal plastisol we are right about 7/8 seconds. i figure im going to have to go a little longer. obviously ill test it out, but figure why not ask to get a head start.




Sorry I seem to have messed with your post. Should be all back to normal now Frog

[dirkdiggler]

how are you coating, that will make a difference.

[cleveprint]

right now we go 2/2

[dirkdiggler]

sharp or round

[cleveprint]

i believe its round. guy that does all our coating is out right now or i would actually ask.

[jvanick]

what mesh count and color, are you adding diazo to the HVP or is it straight?

and do you know what your EOM is?

with pure hvp, 156 white mesh, and 21% eom, we were a 14 seconds for a solid 7 on the stouffer strip during our testing.

21% eom was achieved with round edge, 1 over 1.

with a 1/1 sharp, we were getting around 16% eom.

[ZooCity]

Starlight 3140 with the glass
Fixxons/microjet film
Aquasol HVP, no diazo/straight out of bucket
150/48 mesh, yellow
2/1 thin edge coat (do not coat high eom stencils for wb/dc printing, use the thin edge)
25s

We don't run HVP that much anymore but this is what my screen tech had on the chart.  Expose your screen as long as it can go without losing detail/undercutting.  It's a balance between maxing out the steps on the Stouffer strip and holding the minimum detail you need on that mesh. Disregard any comments about shooting screens in 0.5-7s etc. with the Starlight, at least with glass/film and especially with discharge printing- you want your screens strong, not just imaged.

*EDIT- probably none of us have a device to measure dmin/max but it makes a difference, especially when using a less collimated light source.  Assuming we're all using similar dmin "waterproof" film.  For dmax reference I'll say our positives when held up to a bright light, block it out completely, i.e. you can't see the bulb.  If your positives are more like looking through darker sunglasses you may not be able to burn as long. 

[Orion]

Starlight 3140 with the glass
Fixxons/microjet film
Aquasol HVP, no diazo/straight out of bucket
150/48 mesh, yellow
2/1 thin edge coat (do not coat high eom stencils for wb/dc printing, use the thin edge)
25s

We don't run HVP that much anymore but this is what my screen tech had on the chart.  Expose your screen as long as it can go without losing detail/undercutting.  It's a balance between maxing out the steps on the Stouffer strip and holding the minimum detail you need on that mesh. Disregard any comments about shooting screens in 0.5-7s etc. with the Starlight, at least with glass/film and especially with discharge printing- you want your screens strong, not just imaged.

*EDIT- probably none of us have a device to measure dmin/max but it makes a difference, especially when using a less collimated light source.  Assuming we're all using similar dmin "waterproof" film.  For dmax reference I'll say our positives when held up to a bright light, block it out completely, i.e. you can't see the bulb.  If your positives are more like looking through darker sunglasses you may not be able to burn as long.

Changed that to bold red text, sort of important info

[Itsa Little CrOoked]

25s??

I don't know what you meant by that.

[Frog]

25s??

I don't know what you meant by that.

25 seconds?  Remember he also said to disregard those short times of 5-7 seconds.

[ZooCity]

The starlight runs on seconds, not ltu, there's no integrator.

Good call Orion, not knowing that (I sure didn't when I first started doing wb/dc) could make it nigh impossible to get a successful waterbased print. 

[zanegun08]

I'm super interested in getting a starlight, and even tested one internally.

We would run without glass (Spyder II DTS), and were previously using Kiwo Versa-TEX with Diazo.  In testing in house, it took 80 seconds to properly expose the screen.

We are switching emulsion to the new version Kiwo Multi-TEX which doesn't need Diazo, and should get a faster exposure time.  I'm tentative to buy a Starlight since unless I can get the exposure time to around 30-40 seconds, I'm better off just using my 5K MH and doing 5 at a time.

Anyone have a starlight and use Kiwo Multi-TEX, and can post their real times.  I feel like possibly the times posted would be considered well underexposed at our shop, which could be leading to some of the other threads in this forum where people have issues reclaiming.

I love the idea of a starlight, but hitting anywhere near the 7-10 seconds people claim, just seems so far fetched to me and what I have seen in testing within my environment.  Love the idea, and would love for it to work, just tentative.

[jvanick]

Do you really want 7 seconds tho?  Your exposure latitude would be less than. 1/2 a second....

[zanegun08]

Do you really want 7 seconds tho?  Your exposure latitude would be less than. 1/2 a second....

If that was directed at me, yes I would really want 7 seconds if it fully exposed a screen

But I'm realistic, and if I could get the exposure time down to 30-40 seconds realistically, with a fully exposed screen, then I would get a starlight.  In testing it took 80-90 with a different emulsion.

I know I will never see 7, or even 12 seconds with the emulsion we use, but 30-40 seconds would be fast enough that it would make sense to purchase as we could expose one screen while the CTS is printing another, and keep a constant waterwheel rather than doing 5, moving them to the light.

But we sway to the side of maybe what some shops would call over exposing.

[jvanick]

Zane: I agree on all your points

Exposing a screen as fast as the DTS can spit them out is fast enough for me.