Thank you gordo for quick reply...
Below are the angles that were used. Are these correct.
With new angles there is no screen moire and the results are much better than earlier angles but there is some difference in final print result.
Old Angles
C 75 M45 Y90 K15
New Angles
C 15 M45 Y90 k 75
Back in 2008 or so we also had moire problems from time to time on the Heidelberg 74 and did not know why. We found out from just one of our customers. We tried everything from changing the ink rotation lay down to screen angle swap and the lpi from 175 to 200. For the most part it did not help it would just hide the problem or become less noticeable. So when we brought the Heidelberg sm-52 anicolor we were told to run with a new screen family designed for that press. So one day that same customers had a new job on press on the Heidelberg 74 and the same problem with the moire not at all good. We change out the screen family from (PCC Nominal Euclidean 175lpi) to the (CQS Plus 7.5 Euclidean 175lpi) and know more moires we were not sure why but it does work for us.
Some years later I came across an article on here on the digital camera color gamut. I think it was just that. we still used the CQS Plus 7.5.
Cyan 82.5
Magenta 52.5
Yellow 7.5
Black 22.5
Spot 22.5
@Gordo:
I thought that solving the screening issues you mention above and no moire were the original and best selling points for stochastic screening when it first came out back in the late 80s/early 90s.
Although I still believe a 300lpi or higher conventional line screen is capable of finer detail.
One problem I see with FM screening is because it appears randomly, sometimes it appears in non image areas where it doesn't belong and creates a very light color where there should actually be none. This can be seen in reversed out images, and especially seems to appear around edges that should be extremely sharp and appear to be clean, but when examined under a loupe, are not crisp at all.
Because conventional AM screening does not appear randomly, the edges of images are always clean and crisp. A screened image may appear uneven because of where the screen angle ends, but the dot is either there (partially or wholly) or it isn't, and does not show up in areas that it shouldn't be in.
Personally I would say that overall, I prefer FM screening because of it's obvious advantages with no moire, and (what appears to be) it's ability to screen areas with no rough edges.]/quote]
Yes
But I also see some of it's flaws and think that AM screening has a few advantages as well, especially in the higher lpi range. That's where I think it really shines as far as detail is concerned but unfortunately, it seems that most printers aren't really set up for it and are unwilling or unable to reproduce it. IMO.
Well, if "most printers aren't really set up for it and are unwilling or unable to reproduce it" is not a problem of the FM screening technology - it is a problem of the printshop management. Those who have adopted FM screening do very well indeed with it - both lithographically and economically. I've explained the technical reasons why FM is superior to high lpi AM - what you offer in contrast is opinion without any apparent technical basis. Screening is a technical matter not a matter of opinion. Also, there is no "FM" screening per se, each vendor has their own implementation and some are...crap, while others are brilliant (pun intended).
On a sidebar, I helped set up my local daily newspaper to print with FM screening (Auraia DM 2) using secondhand ECRM violet CtP and they've saved some 25% in ink usage cost ($$$savings) and reduced their advertiser charge backs to virtually zero (when I first met them the stack of chargebacks was nearly a foot thick). Plus they now print near-photographic fidelity with no moirés. They love it and so do their advertisers and sales people.
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