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match proofs when printing stoachastic

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  • match proofs when printing stoachastic

    I print Stacatto and some one mentioned in previous thread about a problem they were having with shadows printing lighter than the proofs when they used Sublema - We have the same problem - it shows up in car typres which on the proofs look black but with stacatto look grey and full off detail - do others have this problem

  • #2
    Re: match proofs when printing stoachastic

    I'm assuming that you are using an inkjet proofer.

    This issue is unrelated to the screening. It can happen with any class of screening.

    The likely causes of the shadow areas in the proof not aligning with the presswork using Staccato or :Sublima are mostly likely one (or more) of the following:
    1) the ICC profile that drives the color on the inkjet is not properly setup
    2) the lower resolution and ink splatter in heavy coverage areas of the inkjet is plugging the shadows on the proof
    3) the press operators are reducing solid ink density in order to compensate for inappropriate tone calibration curves on the plate

    I'd vote for #2 as the most likely cause.

    best, gordo


    • #3
      Re: match proofs when printing stoachastic

      A real quick check of your Inkjet proof compared to a "good" press sheet will answer your question.
      Simply look at the colorbars on the press sheet and compare the solid CMYK bars to the Proof's colorbars.
      There was a theory going around for some years to: set up the Inkjet to "as much density" as could be produced.
      This sold a lot of software but, it did not allow a "proof" to represent a "press-sheet' properly.
      What Proofing system are you using?


      • #4
        Re: match proofs when printing stoachastic

        Our proofers are set up by Kodak using Epsons with Matchprint rips they are about 18 months old - but is is not only our proofs we see it on It others come in from clients -

        I am not sure its the proofer - it happens with car tyres which always look nice and balck on the proof but printing staccto puts detail in so they looks grey - Now the only way stacatto can put detail in is to lighten the black - it cant make it darker . So I am wondering with the type of screen there is more going on than I think

        The 75% tints conform to Fogra on the printed sheet


        • #5
          Re: match proofs when printing stoachastic


          There is nothing special going on with this type of screen. Staccato is like any other halftone screen AM or FM in the sense that the tonality/color you see is a function - in this case and simply put - of the tone curves being used, the substrates your printing on, the densities and ink rheology on press, and the initial press proof to alignment that was conducted. This assumes that there has not been a fundamental change in one of the basic variables - like blankets, inks, paper, plates, etc, etc.
          Do you have a golden reference standard that you can rerun on press (i.e. a file, press sheet, proof and production/plates data) to see if under the same conditions you can rematch the press sheet from when everything was working correctly? This can help you nail down what might of changed in your process that is causing you issues. If you do not have such a reference standard in your shop, the best plan of action is to do some objective diagnostic tests. A press or a halftone screen do not "know" about car tyres - they "know" about max ink coverage, tone values, trapping, density, etc. So you might want to take the subjective tyre image out of the equation and just deal with the tonal elements that are incorporated in the image - that way you might help you break down the problem into its components to isolate which element(s) in your production process is causing you grief.

          thx, gordo


          • #6
            Re: match proofs when printing stoachastic

            Assuming all things on the press haven't changed much I go to the proofer on this. We are a full time Staccato shop and things as you desribed dealt me a fit. We purchased a Veris proofer and I began to see a difference in the shadow areas on the Veris proofer. That pointed then to my Epson 10600 a an issue. We purchased an Epson 9800 and that has helped tremendously. We use an EFI front end on our Epson. I am also assuming that the pressman are able to match your proofs in other areas? We find that when we are correctly calibrated and the loop is tightened down we dont have too much problems matching the proofs on press.


            • #7
              Re: match proofs when printing stoachastic

              Ok, I think the problem is within the proofing. I would suggest that you ask Kodak the leading question: "Was my proofing system set up with a {CANNED PROFILE} or was a press run made and the targets read to get the ICC profile the proofer uses to mimick the press?" Secondly was the proofing system linearized and profiled at your shop or did they again use "CANNED PROFILES".
              What you are describing is the opening of the three quarter and shadow tones seen on the press sheet and not on the proof. I would highly suspect the proofing system was setup quickly with CANNED PROFILES.

              Gordon Pritchard Was right, you should have a "target file" that you can put on the press and any time to see "what changed". This file should have the profiling target for the colormanagement software so you can build an ICC profile and this form should have images of color, halftone, and pastels. I would suggest you put one of these car images with the "tires" you are lookinf at on there as well.

              If you can get the target file printing right then you should be able to match it at the proofing printer.


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