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  • Trapping

    When ripping a 4 color file should I keep trapping on or turn it off? Does it make a difference?

  • #2
    Re: Trapping

    It may need trapping even if it's in process. In fact, each time you have adjacent color areas with no or very little common components, such as a red zone (magenta+yellow) touching a cyan zone you need trapping. The amount (width) of trapping may vary.
    Better train people and risk they leave - than do nothing and risk they stay.

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    • #3
      Re: Trapping

      How's it, Chief.

      There is a lack of educational resources on trapping. The GATF bookstore doesn't seem to have anything on trapping. On Amazon I found one book, +The Complete Guide to Trapping+ by Brian P. Lawler, which I had to order second-hand. It's very dated, nonetheless, while the methods by which we arrive at 'traps' have changed (from vacuum-frames to software) the raison d'etre endures.

      I rely on our RIP's in-built trapping; but I don't trust it. It's scary leaving it all to a computer and not knowing what's going on inside (and it probably traps in a raster format). If our jobs justified it , I would rather have control over how they spread and choke. I think that's what they call 'interactive' trapping - when it's done digitally, but manually.

      Anyone know of good resources or software? Anyone use LucidDream? What's that like?

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      • #4
        Re: Trapping

        Nicolas,

        We offer both in rip and off rip trapping, Our off rip trapping won a GATF Intertech award. It was named Surpertrap and is an Adobe Acrobat pugin. In fact, it was the first true PDF trapping engine. You could trap a PDF and anyone with a Acrobat reader could view the traps. This has migrated over the years to several new versions and also a name change to Prinect Trap Editor. Since last January, we have been trapping transparency. And the traps are editable. So you can batch process files, view and edit if needed. You can also customize trapping rules. Here is link: [http://www.heidelberg.com/www/html/e...itor,overview]

        Chiefs420,

        In North America, trapping is the norm, some countries it is not. I now know from reading Nicolas post it is also used in South Africa, it is not used in some Asian countries. So trapping seems to be accepted or not depending on location. I do agree you would want to trap to avoid flashes of white or color as most of us do in the U.S.

        Regards,

        Mark Tonkovich
        Heidelberg USA
        Product Manager, CtP & Proofing
        Mark Tonkovich
        Heidelberg USA

        Comment


        • #5
          Re: Trapping

          We may or may not trap a 4cp job.. just depends on what common color there is on touching elements. Usually an operator decision, the majority of the time we run it through trapping just so it's taken care of.

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          • #6
            Re: Trapping

            We have a lot of info about trapping and trapping theory on our web site:

            www.trapping.org

            David Lewis
            Lucid Dream

            Comment


            • #7
              Re: Trapping

              The best resource I have found which explains trapping very clearly and provides useful tips for trapping is Exploring Digital Prepress. Click on the link below to go to Amazon:

              http://www.amazon.com/Exploring-Digi...4144963&sr=8-1

              Hope this helps,

              P-Rex

              Edited by: P-Rex on Nov 28, 2007 10:50 AM

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              • #8
                Re: Trapping

                There truly is no black and white rules for trapping it seems. It's religion and is similar to 20 guys debating what is the best beer.

                I think it's important to know how much can be intelligently automated for your particular output (offset, web, flexo) as well as a quickly handled toolset to break those rules when a trap would look better changed.

                The corrugated folding carton boys tend to have the biggest traps and demand the most for mitering, trap trimming and editability.

                I am really curious how those folks in Europe and elsewhere that don't trap feel about going trap-commando. Is it just better press conditions, or they just don't care about a few flashes here and there?

                Grant me the serenity to trap the borders I cannot change and the neutral density to know the difference.
                Amen.
                AL

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                • #9
                  Re: Trapping

                  "Grant me the serenity to trap the borders I cannot change and the neutral density to know the difference.
                  Amen."

                  Allan,

                  ROFLMAO. That's great. I love it. I needed it. Thanks for the laugh.

                  Don

                  Comment


                  • #10
                    Re: Trapping

                    Allen
                    I am in Europe and started trapping using Scitex in about 1995 - I can remember showing clients it the first time - it was only when they pointed out that they thought the black lines were a bit heavy did we reduce the size of the trap!!!.
                    I can remember we competed against Delta -who said they only trapped pages that needed it. Then I think in the Creo/ Heidelberg mess Creo lost the trapping soft ware. We still trap in (Creo/Kodak) trapper. Mettalics still catch us out though

                    Peter
                    we never offer clients the choice - everything we can we trap

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                    • #11
                      Re: Trapping

                      We trap by hand at application level. I had some doozy files that I took around to the in-rip trapping systems and all but one of those systems failed. The one that was successful however, was extremely expensive. This is folding carton trapping with metallic, spot color and process.
                      All of the failing trappers trapped in seconds, some areas correctly and others not. When the parameters were modified to correct the areas that were not trapped properly, they became correct while previously correct areas were now incorrect. Freakin' useless!
                      Because 90% of our work comes in wrong anyway, we tear jobs down and rebuild them to fit our productions dies and glueing equipment and manual trap at the same time as we optimize the files.
                      Our technique is taught within the shop and through our trade school in Toronto for those union members that desire it. I have even been known to hang a shingle the odd time, Have Manual Trap Technique, Will Travel. The course occupies two large four inch binders and is always in need of updating to suit the newer applications, especially now that we have so much transparency in use. BTW, the course covers nearly everything and takes about 90 hrs.
                      A big pet peave of ours is trapping within a Photoshop image. The vast majority of auto trappers do not do this, period. I know of only one that can and it is using the oldest raster trapping technique and therefore works. Object based trapping will not work since the trapping is wanted internally within the object. This problem was exacerbated by adding vector text within Photoshop (such as a bright yellow heading inside a deep blue sea image).
                      Of course we do that trapping within Photoshop on the native file and would immediately extract such an image if embedded, trap it and return to the build file.
                      Trapping is always necessary when printing on recycled cardboard and on any cardboard really if printed offset. I suppose a digital press might get away with less trap and if a single cylinder type device might get away with no trap, but I'd bet a week's wages, it would still need trap if it was printed on cardboard seconds, a common thing nowadays.

                      John

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                      • #12
                        Re: Trapping

                        John,

                        Which program that did auto-trapping actually did it correct? (and was it a PDF trapper?)

                        Don

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                        • #13
                          Re: Trapping

                          Back in 98-99, I did Applications testing for Supertrap on behalf of Heidelberg with the joint venture of Heidelberg/Creo. I did the beta site tour with it. They had the trapper and the color management portion of Prinergy .The rest was pure Canadian code.

                          When Creo decided to write our own color management and trapper, we had Supertrap as a yardstick for PDF trapping. I am proud of the efforts of the team that made a much easier to use interface that still does a really nice job.

                          When Creo picked up Scitex, there was quite the pile of patents that those folks had captured for decades. The decision to write a trapper that had the logic of old, with the PDF body of new was unique.

                          I just saw an AGFA file yesterday that had some traps that nobody saw until output that runs ticketyboo through Prinergy.

                          Many of the features that were tested with the Trap Editor (Creo) were tested with the big boys in folding carton land who had massive traps.

                          My wife still calls me a loser when I judge the trapping on a bus billboard...
                          AL

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                          • #14
                            Re: Trapping

                            Don,

                            It was Dalim and it was using a ps workflow and just before they went on their jdf tear
                            (As you well know, I continue to use native).

                            For pdf trapping, I would look seriously at Neo (although expensive). I was impressed with the stunning power of this app at first glance. However, I have not done an indepth study of pdf trappers yet but expect will have to sometime next year.

                            Cheers,

                            John

                            Comment


                            • #15
                              Re: Trapping

                              John,

                              Thanks for that. Since I already use a raster trapper, I guess I was hoping the one you liked was a vector trapper/object trapper/PDF trapper. I'm impressed with Neo also. Very impressed (would like it in my workflow). I just haven't had the opportunity to test trapping with it.

                              Thanks for your response.

                              Don

                              Comment

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