Super Hot Cyan

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Active member
To make a long story short: Jobs are running fine. Pressmen are printing to density and the press sheets are looking just like the proof.
Job after job after job after job.

Then suddenly, Cyan goes berserk and blows it all out of the water.
The proofs look fine, the plate measurements are fine, but they have the cyan shut off on the press and it's still 25 high. Our cyan press density should be 1.35 and they are running at 1.59.

? Any thoughts ?

Job is 4c PDF from a good, knowledgeable client, treated the same way all the other jobs are treated, it goes thru the same channels that every other 4c job goes thru.
Rip: Nexus
Proofing: GMG to Epson 9800
Plates: Fuji on Javelin 8600 S
Job is running with Concentric Screening. We haven't had any trouble with it .

Everything but the press looks to be right where it should be.
And, of course, I have to spend the rest of my day figuring this out.

Thanks in advance for any and all input!
 
Re: Super Hot Cyan

Hi

your problem sounds like a few issues which i have had recently. i put it down to ink/water ballance and changed to a higher tack ink which picks up a bit less water. i even had the problem when work and turning low coverage jobs. In our case it was caused by a slight over feed of water on the previous jobs which then was made worse by zone changes and startup surges when make ready on the next set. If we washed up and put fresh ink on the rollers the problem would disapear, this was made worse by changes to temperature in the pressroom which required constant adjustments to water feed, at the moment we are trying the stelin resista series of inks and they seem to be a lot better.

Paul
 
Re: Super Hot Cyan

It seems like an unstable ink water (emulsion) balance due to Calcium Carbonate leeching out of paper. Usually people think of Calcium issues only with Magenta ink because the red pigment has Calcium in it. But todays paper has a lot of calcium Carbonate in it. Why the second unit only? The black unit, perhaps, already wets the paper and the make the paper coating weak. The lower ther coverage, less ink film, the higher the tack of that ink. Eventough the ink companies grade tack of KCMY, depending on your coverage, the tack can be higer or lower.
How often do you use Calcium rinse? weekly?. Also the lower the pH of your press ready fountain solutiom, the higher the chance of leeching Calcium out of paper. Try to cut water down in all units, especialy the black and Cyan in your case.
GJ
 
Re: Super Hot Cyan

The ink hasn't changed, it's been the same stuff for quite awhile now. I do know that the guys back there maintain the press very well. However, these are the same guys that had the cyan and magenta plates switched a while ago too, and came into my prepress room waving a press sheet around claiming that our "system" wasn't working.

I could go on and on.

I'll check into all of the issues presented here and see what happens. Problem is, the head guy is a know-it-all and is already dead set on blaming GMG.

Thanks for all the input!
 
Re: Super Hot Cyan

Username:
Seems to me it can't be ink and water balance if the density is too high. You think you have the zones shut down, but they aren't. Maybe you should determine whether the ink blades are zeroed. I don't see how else TOO MUCH cyan ink could be happening. Could be the sweep and ducting of the cyan ink is out of control, then you have to sheet more ink off to get to the target densities, meanwhile the density is fluctuating with each adjustment.
John Lind
Cranberry Township, PA
724-776-4718
 
Re: Super Hot Cyan

If ink is coming through it can't be shut off - shut the water off and try a dry solid and see what happens

Peter
 
Re: Super Hot Cyan

No, the ink isn't literally shut off, that's just a pressman term. I'm not a pressman, but I do know that they can't run job after job with perfect color and then have one job out of the blue (pun intended) just wreak havoc like this.

I also know that the head guy was back there blaming the rollers, then turning around to me and blaming the proofing. So, something doesn't jive here and someone is not covering their bases.

Just had a guy here (a special techie press guy supposedly) take 10 seconds to look at the press sheet then leave. My head guy now says the press is fine and it's all the job files (photos, etc.) that have cyan pounded into them. Funny, but I don't see it, and I don't think my computer is going to make up percentages of cyan just to make me happy. Or does it? Maybe my eyedropper is only saying it's 32% cyan but really printing 95.

rant, rant, rant...I'll stop myself here.
 
Re: Super Hot Cyan

I have re read the question and need to ask, is the problem that the cyan ink behaving unstable, or is it that they need to run the cyan at the higher weight to hit the colour? If it is the second then i understand why you check all plate readings and still cant find why there should be a difference in output on press and why your press guy is blaming pre press.

Paul
 
Re: Super Hot Cyan

they had to run far less cyan to get close to color. that's why I don't understand how everything can be fine until it hits the press. Everything checks out except the press.
 
Re: Super Hot Cyan

Hi Username,

Just throwing my 2 cents in...

Perhaps a curve is not being applied to the plate? Means they would have to reduce the solids (Densities) in order to match the halftones...

But I'm not sure if I'm reading this properly. I believe you said that they were having to run it higher to match, so perhaps too much dotgain compensation.

then again you said you checked the plate...

I Know that low coverage jobs on press are very easy to over-ink.
 
Re: Super Hot Cyan

Dear Sir/Madam,


I will be on vacation on the 3rd April for one day.


If you have an urgent issue or query (support or sales), please email [email protected] or [email protected] as appropriate.


In case of an emergency, please do feel free to contact me on my mobile.


Best Regards,


Andy.


Andy Cave,
Chief Executive Officer,
Hamillroad Software Limited.
www.firstproof.com
www.hamillroad.com
Office: +44 (0)1223 236272
Mobile: +44 (0)7776 258708
 
Re: Super Hot Cyan

Looks like Andy Cave is on vacation after all.

Anyway, the plate curves were applied and are working properly.
I think the best way to check this out is to re-run the plates for the sig that had the most headaches and put it back on the press. Of course, after the guys wash up, zero out, etc. etc. and make a fresh start of it.
 
Re: Super Hot Cyan

How about the file that is being sent to the output device. Are the profiles from the applications the same. Are all the files coming from the same computer or different computers. It may be the profilng could have changed. Example: If an application was updated or upgraded. That profile for your press may have changed too. Go through and just take a peek. It is faster to do this than pull your hair out at the press level. Start at the begging.

Good Luck on your Blue Day
 
Re: Super Hot Cyan

I have checked the profiles, proofing, etc. and they are all ok. In looking at the press sheets, I can see that they also have far too much black and not enough yellow. I don't think they can even pretend to balance the sheet when they've got 2 other colors out of whack.

They just finished a job about 5 minutes ago that went through the same channels the problem job went through. Ran it to density, adjusted it slightly and bingo, looks just like the proof. This is the morning shift and they are starting with a "clean" press.
 
Re: Super Hot Cyan

Not to beat this thing to death, but here's the logic I'm dealing with:

Press Guy runs the front of a job and pumps up the cyan to make the tiny bit of cyan on this job stand out better. Then, turns the sheets over, hangs the plates for the back and complains that he now has to pull cyan out to match the proof for the back side.

Am I insane?
Is there something I'm missing here?
Will someone please tell me that the above information is totally logical?

Edited by: Username on Apr 4, 2008 6:11 PM
 

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