four color process and spot color screening issues

[ByTor]

I seem to be stumped. How would i separate a job that has four color process vignette going over two or more spot colors without gaining a moire?

I use Esko Graphics Barco system and ArtPro to Kodak XP4 proofing system. Digital files are submitted to printer for plate output.

Thanks

[hoking]

You have to change the screen angles, so each color is 15degrees apart, or at least so that no colors have the same screen angle.

[hoking]

wait, are you saying the plates are being done at a different place? Then it should be there responsibility to change the screen angles for you.

[tuff_gong]

The day I ask a client how to angle my screens is the day I go back to teaching......is it 3:00 yet?

[hoking]

sorry, i did not get your comment.

[ByTor]

It is up to us - the separator - to present the scenario to the customer. Again, our concern (obvious) is that with a 4C vignette next to 2 line colors (with tone) a moire will become apparent.

I've used all my available angles for the vignette!

What magic can I do to the file so I don't get the unwanted moire?

My customer loves the vignette!

[tuff_gong]

A little dithering or gaussian blur? Better than that would be stochastic screening, I guess.
I have heard that moire can be minimized by running a job in two passes - e.g., run the 4/c, let dry, then back through with the spot plates.

[clod]

Is it possible that you could use the yellow channel at the deviant angle? ...harder to see patterns in the yellow

[tuff_gong]

Originally Posted by hoking

sorry, i did not get your comment.

Which one?

[ScottRRD]

Originally Posted by ByTor

I seem to be stumped. How would i separate a job that has four color process vignette going over two or more spot colors without gaining a moire?

I use Esko Graphics Barco system and ArtPro to Kodak XP4 proofing system. Digital files are submitted to printer for plate output.

Thanks

Sthocastic screening is the way to go. The thing you will need to watch using stochastic is that some metallic inks(if you are using them) will give you a pattern. No pms colors that I am aware of will give you these patterns. Make sure your paper is a #1 or #2 grade also.