Author Topic: This is killing me...  (Read 3824 times)

Offline Sbrem

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This is killing me...
« on: July 31, 2013, 10:40:48 AM »
8 color on black, all films output at 55 LPI, 22.5°, elliptical dots. One of the screens is giving us a horrible moire pattern against the others. Checked and double checked. Can anyone recommend a different angle I could use for just that one color? Printed alone, no moire. All other colors are fine. I would like to try just making the one more screen, before I decide to output the entire job again...

Steve
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Offline blue moon

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Re: This is killing me...
« Reply #1 on: July 31, 2013, 10:57:04 AM »
8 color on black, all films output at 55 LPI, 22.5°, elliptical dots. One of the screens is giving us a horrible moire pattern against the others. Checked and double checked. Can anyone recommend a different angle I could use for just that one color? Printed alone, no moire. All other colors are fine. I would like to try just making the one more screen, before I decide to output the entire job again...

Steve

went through the same thing yesterday. I kept printing one film at a different LPI. 'almost certain that's your problem, can't think of anything else that would impact only one screen that prints fine otherwise.

pierre
Yes, we've won our share of awards, and yes, I've tested stuff and read the scientific papers, but ultimately take everything I say with more than just a grain of salt! So if you are looking for trouble, just do as I say or even better, do something I said years ago!

Offline Zelko-4-EVA

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Re: This is killing me...
« Reply #2 on: July 31, 2013, 10:57:19 AM »
we output 60 LPI @ 22.5 with wasach

does the film have moire or the screen?

http://printwearmag.com/article/screen-printing/how-to-print-halftones

from the article= 14 degrees
« Last Edit: July 31, 2013, 11:02:12 AM by Zelko-4-EVA »

Offline Parker 1

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Re: This is killing me...
« Reply #3 on: July 31, 2013, 11:02:53 AM »
8 color on black, all films output at 55 LPI, 22.5°, elliptical dots. One of the screens is giving us a horrible moire pattern against the others. Checked and double checked. Can anyone recommend a different angle I could use for just that one color? Printed alone, no moire. All other colors are fine. I would like to try just making the one more screen, before I decide to output the entire job again...

Steve

I kept printing one film at a different LPI.
pierre

Did the same thing, rechecked the films with a loupe. 

Offline blue moon

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Re: This is killing me...
« Reply #4 on: July 31, 2013, 11:14:33 AM »
easy way to check this is to stack the films on top of each other. If the pattern is there, it's in the films!
You should also place the film on the screen and look for the pattern. If it is visible there, the issues is in the mesh to halftone interference. It does not sound like this is the case though . . .

pierre
Yes, we've won our share of awards, and yes, I've tested stuff and read the scientific papers, but ultimately take everything I say with more than just a grain of salt! So if you are looking for trouble, just do as I say or even better, do something I said years ago!

Offline 3Deep

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Re: This is killing me...
« Reply #5 on: July 31, 2013, 11:26:22 AM »
I know you guys know way more than me, but I've run into this also using all the same angles, and what I did with the problem film was double the angle on that film and it worked fine.  Say your using 22.5 then I would bump to 45.5 or do 56.5 can't say why, but once I match the film up under light they look fine and printed great..

Darryl
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Offline Sbrem

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Re: This is killing me...
« Reply #6 on: July 31, 2013, 02:03:16 PM »
8 color on black, all films output at 55 LPI, 22.5°, elliptical dots. One of the screens is giving us a horrible moire pattern against the others. Checked and double checked. Can anyone recommend a different angle I could use for just that one color? Printed alone, no moire. All other colors are fine. I would like to try just making the one more screen, before I decide to output the entire job again...

Steve

went through the same thing yesterday. I kept printing one film at a different LPI. 'almost certain that's your problem, can't think of anything else that would impact only one screen that prints fine otherwise.

pierre

That was my first thought of course. So out came the loupe to check angles and line count (compared to the other films) Yes, the first one was wrong, so I output again, the one film, and it is correct. It's a really strong one moire too. Looks like re-outputting the whole thing...

Steve
I made a mistake once; I thought I was wrong about something; I wasn't

Offline blue moon

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Re: This is killing me...
« Reply #7 on: July 31, 2013, 02:12:52 PM »
8 color on black, all films output at 55 LPI, 22.5°, elliptical dots. One of the screens is giving us a horrible moire pattern against the others. Checked and double checked. Can anyone recommend a different angle I could use for just that one color? Printed alone, no moire. All other colors are fine. I would like to try just making the one more screen, before I decide to output the entire job again...

Steve

went through the same thing yesterday. I kept printing one film at a different LPI. 'almost certain that's your problem, can't think of anything else that would impact only one screen that prints fine otherwise.

pierre

That was my first thought of course. So out came the loupe to check angles and line count (compared to the other films) Yes, the first one was wrong, so I output again, the one film, and it is correct. It's a really strong one moire too. Looks like re-outputting the whole thing...

Steve

picture?

pierre
Yes, we've won our share of awards, and yes, I've tested stuff and read the scientific papers, but ultimately take everything I say with more than just a grain of salt! So if you are looking for trouble, just do as I say or even better, do something I said years ago!

Offline ScreenPrinter123

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Re: This is killing me...
« Reply #8 on: July 31, 2013, 02:20:32 PM »
I was told 61 degrees as a sure fire angle by two isolated sources who were keynote presenters at SGIA about 4-5 years ago in New Orleans.
« Last Edit: August 01, 2013, 10:21:57 PM by ScreenPrinter123 »

Offline Sbrem

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Re: This is killing me...
« Reply #9 on: July 31, 2013, 02:33:25 PM »
I was told 61 degrees as a sure fire LPI by two isolated sources who were keynote presenters at SGIA about 4-5 years ago in New Orleans.

I've used 61 as well. But it's not in the screen, it's on the other inks. It's just one out of 8 films. After enough hours of thinking, it's time to re-output. Onward...

Steve
I made a mistake once; I thought I was wrong about something; I wasn't

Offline Sbrem

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Re: This is killing me...
« Reply #10 on: August 01, 2013, 09:16:51 AM »
OK, all new films, and at 61°. Much better now. Thanks for the help everyone. Sorry the pic is a little fuzzy...

Steve
I made a mistake once; I thought I was wrong about something; I wasn't

Offline Parker 1

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Re: This is killing me...
« Reply #11 on: August 01, 2013, 09:29:54 AM »
Really nice print! 

Offline 3Deep

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Re: This is killing me...
« Reply #12 on: August 01, 2013, 10:56:30 AM »
Looks good Steve glad I taught you all I know LOL, which would have been a one color print with funky halftones :-[

D
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Offline Sbrem

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Re: This is killing me...
« Reply #13 on: August 01, 2013, 11:26:21 AM »
You could do similar work Darryl, even with less colors, don't sell yourself short, man.

Steve
I made a mistake once; I thought I was wrong about something; I wasn't

Offline ZooCity

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Re: This is killing me...
« Reply #14 on: August 01, 2013, 05:31:49 PM »
Steve, do you guys run S mesh?  Murakami has a nice "decoder" sheet for this, presuming it was mesh to line angle issue. 

http://murakamiscreen.com/wp-content/uploads/2012/07/HalftoneAnglestopreventmoire.pdf

I do wish there was a 60lpi on 330/30 guide but this gets ya close.