Aqueous on Uncoated Stocks

[bblakley]

Bringing up the age old question, "Does putting Aqueous Coating on an Uncoated Sheet do any good?". I have a job coming up where the customer (who is always right) wants to put a Flood PMS 186 on a Sheet of 160# DT Classic Crest Cover and seal it with Aqueous so it doesn't scuff. (Text paper is a 100# Uncoated Opaque so that doesn't help with the Scuffing) My experience tells me that the AQ soaks into the sheet like a sponge and that it will still scuff anyway. Does Dry Trapping the Aqueous in a second pass make any difference? Special kinds of AQ made for Uncoated?? I have worked with some people who's experience I respect who will use AQ on uncoated, and other people who I equally respect who simply won't do it. What I would like to do here is get your opinions and tally how many people are for it, and how many against. Of course if you have any experience or tricks that make this work, I'd like to know too.

Thanx, Bryan

 

[RGPW17100]

Yes it makes a big difference on a solid. We dry trap on uncoated. We buy a non curling uncoated aqueous but a regular one will work on cover stock. If you let a solid red dry for three days and rub it hard with your fingers you will pull some of the red pigment off and your finger will be red. If you aqueous it this will not happen. We have a five color and the other benefit this offers is you can de powder on the print units so the solid does not have a sand paper feel. Biggest problem you will face is the aqueous will burn the color. I am pretty sure 186 will have to be a coatable ink. Your press operator is going to have to guess what the color will be after the printing then after the aqueous. Your ink company might be able to help you out with this. They can give you a wet density to hit when printing the red ink so when your ink burns out from the aqueous it will be the right color.

 

[GJOHN]

RGPW17100,
The ink formulator will use special pigments that will not change color under the aq. coating. No need for the pressman to guess the color after it "burns" under AQ, or UV coating. The ink company can pull a swatch and apply the aq. coating to half of the print and this will show the color with the coating. This can be approved by your customer and can be signed off by the customer. If the ink formulator does not ask if a PMS/special color will be coated or not, he/she is not doing the right job.

 

[RGPW17100]

When we order coatable inks we do not get draw downs. In Bryans situation I would agree that a draw down should be received from the ink company. We do not ask for this because we very seldom aqueous coat an uncoated sheet. We typically run the color inline but back traping and proper ink drying are issues when coating an uncoated sheet. Not only would I recomend a draw down but also wet densities. Doing this usually requires giving the ink company paper samples and aqueous samples if not purchased from the ink vendor.

 

[bblakley]

AQ on Uncoated

AQ on Uncoated

Can you do survey's on Print Planet? I'd be curious to see how many printers think AQ on an uncoated sheet actually works.

 

[RGPW17100]

Our packing lists have a double solid hit of 485 on the back. We hit it with Satin Aqueous then back it up. We use a van son hard dry ink and without the aqueous the ink chalked severely. A varnish will do the same thing but not as well.

 

[wildwhl]

We use a satin AQ, wet trapped, in situations like this with great success. Works well on the heavier sheets...and as you know, works great for turning the text weight stock into mail tubes in the delivery

WW

 

[viclpp]

do you have to run the aq coat on a second pass or can you just run it in one pass? wasn't sure if this will make a difference

 

[RGPW17100]

You can run it inline on the first pass. If the coater starts to back trap the ink you need to apply more coating.

 

[nhprinter]

We have quite a few jobs like this. Mostly business cards with a full solid on the back side. We don't have a coater, but we'll varnish inline with a satiin varnish and then varnish them again the next day to fully protect them. It's been our experience that just running the varnish inline didn't do much good and this way we can also adjust the color on the first pass. The color will not change with the second pass of varnish.

I would assume this would work the same with a coater.

 

[turbotom1052]

Heres something that ive done that has worked for me. If no coater is available, and your running a solid on an uncoated sheet you can take for example a can of pms 185. Reduce the can of 185 by half with a good hard dry varnish. Gloss varnish would be preferable!!! then print the solid as a double hit. Try to spread out the units you print on if possible, and if possible run the solids dry (no water) Ive found that on most uncoated sheets the ink films dont lay in distinct "layers" It all gets mixed together as it penetrates the pores of the stock. The hard dry varnish will bring it all together with a pretty decent rub resistance.
Of course if you have a coater available that would be my first choice. And if theres enough money in the job to coat the solid offline that would be optimum but not really needed. Most coating manufacturers sell an aqueous coating formulated for low curl on an uncoated sheet. Without that coating you should expect your sheets to come out of the delivery like a bananna.

 

[ReflexBlueHorror]

Yes it makes a big difference on a solid. We dry trap on uncoated.

I was enjoying this thread but I'm confused as to what the sequence of operations ultimately became...

Was it Printing & coating in one pass, drying then coating again?

Will that have changed the appearance/texture of the uncoated paper?