Cryocoat failing me

[Hey Monkey]

I have tweaked exposure times, 1:1 coat to 2:1 coat and it is still breaking down. Especially under Discharge. Not getting past 100 prints (all manual btw) I am sitting at 1:20 for my exposure time (brand new Vastex 4731 UV Bulbs). I am not using the Cryoprep and honestly, if I have to to make the emulsion work properly then no thank you. I was using Textil PV and never had these issues with 1:1 coat and 40 sec exposure with post-expose.

Up exposure time more is all I can think of... But again if I have to up that much I might as well go back to what I was using and save the time and headache. Everyone talks so highly about this emulsion I am surprised this is happening to me.

[DannyGruninger]

It's your light source quite honestly..... All we use is this emulsion and we have done 54,000 prints on one screen with hsa ink without breakdown. Daily we do 500+ pcs jobs using discharge or waterbase with no breakdown. When we first tested we had breakdown but it was linked back to under exposure which I can assure you that is what is happening. It's our go to emulsion regardless if we are doing sim process, spot work, or ink we use. Proper exposure is key

[Hey Monkey]

Thanks Danny... What are your exposure times? This is a pretty new Vastex Expos-it 4731. Vaccum lid. Using the guidelines the top end of the exposure time is 55 sec but that is not working at all.

[Frog]

This looks like a job for...

[Hey Monkey]

This may be a stupid question but how do you step test with a vacuum top unit?

[Colin]

Put something like a manila folder under the film you are using for your step wedge tests.  Mover it each time you do a new step.  Yes, you will have to go through the vacuum step each time.

[Frog]

You either use a calculator that has the steps built in (like the Stoufer or even the giveaways from folks like Ulano) or like Colin said, you stop and start the process however many steps you are making.
Expose, stop, open, move the opaque step film, repeat.

[Hey Monkey]

The issue is I am getting great wash out and perfect detail then break down on the screen once in use. So how will I really know which time is the best if it looks like it clears nicely at 55 sec (but does not work over the long run)

Did that make sense?

[Colin]

That emulsion likes to be over exposed.  I use another version of that same emulsion.

With my Nuarc 3140 1200w Metal Halide bulb.  I expose my 150 (1x2 coat) at 110-130 light units.  Which equates to a little over 2 minutes.  Like I said, this emulsion LIKES to be over exposed.  I still have phenomenal detail hold.

Try exposing for 3 times longer than necessary - just to see what happens.

[Frog]

Colin touched on it jut before I could post, but
how much can you expose over the 55 seconds and not have small areas close up?

[jvanick]

are you post exposing either in the sun or back on your exposure unit for 3-4x the original exposure time?

for waterbase work (and I also do it for long run plastisol), this emulsion needs to be post-exposed to get to the optimal hardness

[ericheartsu]

are you post exposing either in the sun or back on your exposure unit for 3-4x the original exposure time?

for waterbase work (and I also do it for long run plastisol), this emulsion needs to be post-exposed to get to the optimal hardness

especially with this emulsion x 10000000

[im_mcguire]

I had a similar problem when I was exposing on my UV exposure unit.  I was using Murakami sp-1400, Alan Buffington walked me through what my issue was.  Ultimately the UV bulbs were not properly cross linking the emulsion for proper exposure for the discharge.  I was exposing at almost 2 minutes, but with my UV output Alan told me it would almost take 11 minutes for proper cross linking to occur.

He had me try a exposure in the sun, and once I did that, I had no more breakdown.

I know the emulsion is different, but I think the lack of proper cross link is your issue on this...

Like Danny said... "its all in the light source" UV bulbs are not great for WB / DC from my experience.

[Hey Monkey]

No nothing I can do about the unit so upping Exposure time and post exposing is where it is at then!

[im_mcguire]

No nothing I can do about the unit so upping Exposure time and post exposing is where it is at then!

All you would need to do is expose 1 screen in the sun and eliminate the thought of it being bad emulsion.  Do a sun exposure at 55 seconds, and then post expose and let it dry in the sun, you should be good.  I used a piece of glass to weight down my film.  I took it old school to eliminate variables on the exposure end...