FM Screening Implementation Process

[jotterpinky]

Does anyone know of a good source (person, printed guide, etc) to implementing and testing a move to FM screening?
I've read Gordo's posts on the benefits, and a number of other sources including information on my specific RIP and CTP system. However I'm still a bit shaky about taking the plunge and would like some resource to rely on for questions or consultation. Any thoughts? Perhaps lessons learned from those who have already done so or perhaps even reasons for not having done so?

From my understanding this is the process one would follow:
1. Determine the dot size your equipment and plate is able to handle. In my case I think a 25 micron would be a good start. Our CTP device manufacturer as well as our plate dealer claims we can image a 20 micron dot and hold it.
2. Obtain the "screen" for your RIP
3. Plate some test forms in their RAW (no curves / color management) form using the new screen.
4. Run up to color on the press, reaching ISO ink densities for sheetfed offset. Pull some sheets and use your densitometer to either a)input into software to create a curve or b)create a curve by measuring the patches and inputting either the software generated curve or the hand generated curve back into the RIP to obtain the correct TVI (dot gain)

These steps seem to be the entire process but I know we're missing some like: Tear your hair out when it doesn't work, type of steps.

I would appreciate some feedback.

 

[BeauchampT]

Our plant recently did this in conjunction with a sister plant. The run of 25 micron dot went very well. In fact, we used the dot calibration curve we were currently running to match teh Fogra 41 icc profile and found that it got us 75% of the way there for the right dot gain curves and colour targets with FM. The ink savings in yellow and black ink were pretty good.

All in all, it was actually a fairly easy process.

One thing about it though: in the higher screens you could still see patterns (like snakes) - the randomized dot laydown of FM still develops odd patterns at times. When we had a variety of operators do a random check of the print (without looking through a loupe), many of them saw only small improvements using 25 micron FM compared to 150 lpi AM

Hope it goes well for you.

 

[Prepper]

We did this 2 years ago and haven't looked back. Many trepidations to start with though, salesmen asking "why do you want to, nobody else in our area does" saying "it's too hard" etc, etc. We finally got a 30 day trial of the screening for our rip and tried it. No problems on press, which surprised us, and much finer screening so much better detail, so I can't understand not being able to tell much improvement over 150 when even I can still see those dots without my readers.

Try it and see is the best way, you'll know then what your experience is, things aren't usually near as bad as the fears of what could happen. The benefits far outweighed the negatives for us.

Go for it!

 

[gordo]

@jotterpinky

You're basically right...but I would add:
1 Make sure that you currently have a reliable, stable, consistent print production process. That your press operators are not making or fixing color on press.
2 That they buy in to making the change and understand why.
3 Make the change 100% - don't reserve FM for just special jobs.
4 Confirm that you have good ink transfer and emulsification on press.

Some printshops will create tone compensation curves much as you described to bring the tone response of FM to their existing AM screening - then leave it at that. Others will go further and characterize their FM presswork and build a profile to align their proofs more closely to the presswork.
25 micron is typically used for coldest and heatset webs. Lithographically it's close to 175-250 lpi so it is not too different from what you're currently using. Which should make things easier.
There are differences between the patterns used by the various vendors - even when they seem derived from the same base or they look superficially the same under a loupe. Some may show patterning in presswork, as HDS sometimes will while another, like Staccato, don't - even though the screens may appear to be the same (they're not).

Best, gordo