Re: G7 and Flexographic Printing
Re: G7 and Flexographic Printing
- Subject: Re: G7 and Flexographic Printing
- From: Roger Breton <email@hidden>
- Date: Thu, 23 Aug 2007 10:20:45 -0400
Bill,
> One of our major problems is with gearmarks on the printed samples.
It seems to me your company would benefit a lot in investing in a solution
to get rid of those gearmarks. But that maybe a function of the age of your
presses -- you seem to have "hybrid" flexo presses, a combination of ink
fountains, like on an offset press, and anilox rollers, like on a true flexo
press.
> I use an iO table to measure the patches in the office and a 528 to
> measure the press run on site. I have some discrepancies in numbers
> between the two devices and would appreciate some feedback.
There is nothing wrong with using an iO to read the P2P targets. But you
have to keep in mind that it's going to be hard to hit the exact same spot
that was read by the iO with a 528. Thereby explaining some of the
differences in your readings, IMO. (But there is a difference between the iO
and the 528 anyway, thank's to the difference in traceable standards of both
instruments).
> 1 - Other than the black, knowing the tolerance for G7 is 5 dE,
I must have missed this figure in the G7 documentation altogether, Bill :
would you care to cite where this figure is stated?
> would
> you all feel comfortable running with these dE's to the standard?
On a flexo press, 5 dE does not seem far fetched anyway.
> I
> have a gut feeling that the color of the black is very important
> because gray balance from CMY is trying to match the black.
That is not true. Ask Don. He'll tell you that he's not trying to match the
shade of black with CMY. The CMY target aims are a function of the
substrate, not the black. Blacks can be warm and they can be cool. If CMY
was trying to match the hue of the blacks, G7 gray balance would be all over
the place.
> What, if
> any problems will I create by allowing our black to be this far off
> in dE to the standard?
See above. That is not relevant. Unless I missed something.
> 2 - What does it mean when a color "hooks" in the Analyze portion of
> IDEALink?
All presses do that, Bill, ALL OF THEM. Does not matter flexo or offset or
gravure or what-have-you. It's the nature of progressing away from the color
of the substrate.
> When I ran my linearized run there were no hooks, but when
> I ran my 1st G7 curve there is a hook in the blue. The yellow,
> magenta, cyan and green curve lookws the same on both runs, but as
> mentioned the blue hooks and the red on the curve run, curves the
> other way from the way the red ran on the linear run.
If you are doing a validation run, all you care is that the calculated
deviation are close to zero percent on all four colors. Color will still
hook.
BTW, are you also creating some custom ICC profile through these G7 runs?
> -Bill-
Roger Breton
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