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Super Hot Cyan

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  • Super Hot Cyan

    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!

  • #2
    Re: Super Hot Cyan

    washup, start fresh


    • #3
      Re: Super Hot Cyan


      Do you have a new batch of ink.



      • #4
        Re: Super Hot Cyan


        Edited by: Andy Cave on Apr 4, 2008 4:04 PM


        • #5
          Re: Super Hot Cyan


          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.



          • #6
            Re: Super Hot Cyan


            Edited by: Andy Cave on Apr 4, 2008 4:05 PM


            • #7
              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.


              • #8
                Re: Super Hot Cyan

                is this localized, or over the whole sheet/web?


                • #9
                  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!


                  • #10
                    Re: Super Hot Cyan

                    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


                    • #11
                      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



                      • #12
                        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.


                        • #13
                          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.



                          • #14
                            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.


                            • #15
                              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.


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