Printing Crappy 24pt paper, Sceens not printing smooth

[pacart]

We are printing covers to spiral bound notebooks for a local school, they are 2 color on a pretty rough 24pt cover stock. We can't get the 60% black screen to print smooth, any ideas? Photos attached. We are printing on a 2 tower Ryobi HXX We use Nexus as our Rip so if there is anything Nexus can do please let us know, thanks.

 

[Jimbo]

On that stock I'd lose that screen altogether and print it as a solid gray.

I wouldn't even bother pulling my hair out trying to lay a clean screen on that stock.

 

[pacart]

Are you saying pick a PMS gray and use that? I think that would work but we also have solid black spots on there as well and another small area of a differenct screen percentage so that would take a 2 color project and turn it into a 4 color.


I forgot to mention, the red pms color appears to get smudged as well when we lay down the black. so for now we are letting it sit over night to dry and hopefully solve that problem.

 

[Jimbo]

Some one might have another suggestion but yeah I'm saying throwing in another pass using a PMS. I understand the dilemma and cost efficiency of doing that but board stock doesn't necessarily have the greatest quality as far as smooth finishes go for stock.

Might have to dust the paper through the press on impression. That should take off a lot of the crap building up on your blanket that's destroying your screen.

 

[maynardsayswhat]

I have to agree with the solid custom color being easier with better results than trying to force a screen on that substrate. Sadly this makes it a 3-color job of course.

If any ink is smudging on that stock you may have a simple density issue, i.e. laying down too much ink? Might be on press or your rip isn't calculating ink spread correctly for the more porous stock. Those two things are what I'd check first.

Good luck!

 

[pacart]

Ok so we don't get too fancy around here. That being said, can what you are saying maynard be achieved by using a lesser line screen? We don't usually mess with the line screen, but it is at 175lpi. Otherwise we don't have settings for papers in our rip.

 

[maynardsayswhat]

It doesn't look like the red is a screen at all from the image so LPI and spread aren't probably the issue with the red as much as the grey.

Ink spread is how much the ink physically "spreads" into the fiber of the substrate. Take a drop of water and plop it down on a paper towel then watch how the water spreads into the fiber. The total coverage is larger in diameter than the original droplet of water. This can be compensated for in many pre-press systems and rips for very porous substrates but it's not a cure-all. Check your manuals just in case.

Other than that, the red smudging issue might simply be too much ink being laid down. Not all papers respond the same to the density of ink being placed on it. Try lowering it and see if that helps.

If tightening up the keys doesn't fix it... I guess print in smaller stacks to avoid offsetting and clear some table space or pull out a drying rack and dry them overnight.

Good luck.

 

[rich apollo]

1) drop the screen ruling - 175 lpi is too high for that stock

2) Run the gray as a solid PMS with a screen. You're printing a 'paint job'. Running the solid and screen will give a smoother appearance.

3) Is the other side of the stock any better?

 

[ThePrinter]

You can try sizing the sheet (hitting it with a pass of varnish). This will help fill in the pores of the sheet and provide you with a smoother surface. May screw up your timeline, however.

 

[Jimbo]

pacart, how did this job turn out? What process did you finally go with?

 

[D Ink Man]

The Printer had a good recommendation. Underprinting with a size, dry trap, if possible wil remedy the 'crap' sheet. Hi solids U.P. would be ideal. D

 

[Jimbo]

I'm not so sure about sizing using a varnish. In fact I've never heard of over printing on varnish. You risk reactivation, set off, and quite possibly a job that doesn't dry. Transparent white, maybe, but both of them begin to dry yellow fairly quick destroying the pms overlay quality on the sheet. I stick with laying a pms with said knockouts and praying for perfect feed registration.

 

[spigot]

grey solid or change you ruling and or screen value and ink flow may help, reduce ink down a bit and smash it with max pressure.
Also see some banding there