UV Opaque White

[fireplug55]

Old problem with no answer.

For about 14 years I was an offset pressman running stricktly UV inks on foil board. Now I am a supervisor running into the same problem.

Problem:
While running Opaque White we get a very light haze over the entire sheet. If you ran your finger across the sheet it will come off. This Lt haze takes away the shine of the foil.

I attribute this problem to the water. When running a dry plate we have no issues.

In my days running a press our water mix was with alcohol / acid base and we experienced this haze issue.

Now as a supervisor we are alcohol free and experiece the same problem.

If you have experienced this problem and have any ideas please let me know.

[inkdoc]

hello,

here's what i think may be happening...
the fount soln you r using may be too acidic for the white ink..try increasing the pH of the fount solution..this may help the fount soln to not "bleed" some components off of the ink.!!

this is just a possibility..you may have already gone this route !!!

[Cornishpastythighs]

We experience this now and again running UV opaque whites. It is usually worst when the white is being printed with one hit (excessive ink misting) when we run white with 2 hits using lower ink key settings on each unit it is ok. We are lucky enough to have print units to print opaques using 2 units.

[rchamness]

I agree, two hits should help the problem and a less acid ph will also help. All that being said there are some really good new super white dispersions that we have been having great success. They seem to cover and print better.

[fireplug55]

I agree with two hits, but gave no thought to the lower acid. Will give that a try.

Does anyone recommend a particular white or vendor. Most of our experience was with Flint, Wikoff and Superior. The last being the best in my experience.

Last question, do you adjust the opaque white before putting it in the fountain. In other words do you reduce, or extend it.

[Cornishpastythighs]

We just take it out of the can and use it without any adjustments. We use Flint but I hear that Sun may have a decent Opaque white that we might try also.

[Bob Peterson]

I agree with two hits, but gave no thought to the lower acid. Will give that a try.

Does anyone recommend a particular white or vendor. Most of our experience was with Flint, Wikoff and Superior. The last being the best in my experience.

Last question, do you adjust the opaque white before putting it in the fountain. In other words do you reduce, or extend it.

I would check with your local Superior rep. I know for a fact that they have recently done a substantial amount of work with UV Opaque white. I would check with them to see if you have tried the latest product.