Spot UV Varnish

Ask or answer questions related to the flexo pressroom environment

Moderator: Frank Burgos

Spot UV Varnish

Postby swelch » Wed Oct 03, 2018 11:00 am

Mark Andy P-5 flexo press. We are trying to do spot uv varnishes on shrink - varnish on 1 side, actual print on the other. The problem we've run into is that with shrink through the turn bar for d/s, registration tends to walk a bit even with the auto registration and its almost impossible to see reg marks for the varnish during the run. Is there any trick to being able to see the reg marks for the varnish to hold registration?
swelch
 
Posts: 4
Joined: Wed Jun 20, 2018 8:51 pm

Re: Spot UV Varnish

Postby Gory » Thu Oct 04, 2018 7:49 am

is there any OB in the varnish - if so a black light will illuminate it, although you will have to have it in a very dark area to be able to see
Gory
 
Posts: 40
Joined: Fri Oct 17, 2014 10:08 am

Re: Spot UV Varnish

Postby swelch » Thu Oct 04, 2018 9:43 am

There is optical brightener in the varnish. Apparently some ‘test’ were done with this a couple of years ago shortly after getting the P-5 and they had no success. I don’t know the specifics of what was done other than the use of OB and blacklights. I was on a different P-5 in a different building at the time. I’m not sure what the industry standards are for doing spot varnishes. I doubt there was any really dark area used as the production area around the press is very well lit. The only info I’ve gotten on this via work is ‘other places do it’ and a lot of ‘well this person said’ lines coming from one of our sales person. We can do it, it’s just slow and aggravating and I’m sure there’s got to be a more practical way to do it. Would adding a black light at the inspection camera and boxing that area out work, or would the camera flash kill that?
swelch
 
Posts: 4
Joined: Wed Jun 20, 2018 8:51 pm

Re: Spot UV Varnish

Postby Gory » Fri Oct 05, 2018 10:28 am

I suspect the flash might kill it/ overpower the black light. Would it be possible for you to tint the varnish? (put a very small amount of color in it, just enough to make your registration mark visible, but without overly affecting the overall appearance on your design)
Gory
 
Posts: 40
Joined: Fri Oct 17, 2014 10:08 am

Re: Spot UV Varnish

Postby swelch » Fri Oct 05, 2018 7:02 pm

It's possible that could work. As is, I can catch glimpses of the varnish mark, but usually its just a ghosting here and there that is enough for you to say its there, but not enough to really see the alignment. A slight increase in tint might clear that up easily without affecting anything color wise. That could vary depending on the art of a given sleeve, but worth testing.
swelch
 
Posts: 4
Joined: Wed Jun 20, 2018 8:51 pm

Re: Spot UV Varnish

Postby Buck from N.C. » Sat Oct 06, 2018 7:13 pm

Get the graphics department to make the lines longer on the crosshairs of the varnish plate. Should make it easier to see.
Buck from N.C.
 
Posts: 42
Joined: Sun Sep 23, 2012 1:51 pm

Re: Spot UV Varnish

Postby longtimefan » Sat Oct 06, 2018 10:04 pm

Get ink rep involved for the right OB, if not already done.

If tinting varnish won't work.
longtimefan
 
Posts: 97
Joined: Sat Jun 13, 2015 1:10 pm

Re: Spot UV Varnish

Postby Frank Burgos » Mon Oct 08, 2018 10:53 am

I may not envision things correctly, but would it be possible to add a black station to the same pass as the varnish, register a tiny mark on the black to the varnish and then watch the black for creeping registration with the other, printed side?
Frank Burgos
Site Admin
 
Posts: 963
Joined: Wed Dec 31, 1969 8:00 pm
Location: North Carolina

Re: Spot UV Varnish

Postby beardedcamel » Wed Oct 10, 2018 12:03 am

Can you move you turn bar to the last unit after you lay down a slip coat. This will help with the friction through the turn bar as well as allow you to register varnish top side as opposed to registering print to the varnish.
beardedcamel
 
Posts: 3
Joined: Sun Apr 01, 2018 12:32 am


Return to Pressroom

Who is online

Users browsing this forum: Bing [Bot] and 10 guests

cron