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  • I have a dream!?

    Hello All,

    I work for a large reprohouse in Europe handling a variety of different jobs using process & spot colours, printed on different substrates or virtual every different print process know to man! In the past we have sold ourselves to customers that we will deliver press read files to the printer. As we have grown in customer base & along with the amount of different printer we deal with all over the world it has become increasing difficult to manage the standards we tailor each individual file too. My take on this is that off course we should separate a file correctly while also taking into consideration the print process being used but not take it as far a individuals printers press profiles as potential this could mean our Epson GMG system having hundreds of different profiles on. I believe we should have establish standards for the different print process's (Offset, Gravure & Flexo) & then the printer should print to those standards.
    The questions I would like to ask it is this meanly a pipe dream as we have negligible influence on how printers print?
    What existing standards are in place & are commonly used?, I keep seeing ISO12647-2 mentioned?
    What standards do you currently work to?

    Thanks
    Chief

  • #2
    Re: I have a dream!?

    We currently print to a custom press setup that tries to match a SWOP separation (as seen in Photoshop when not doing soft-proofing but using Adobe's default CMYK profile for U.S., U.S. Web Coated (SWOP) v2) for all customers but one, and am in no hurry to implement GRACoL2006_Coated1v2 for our other customers because they haven't complained and our printing is close to GRACoL2006_Coated1v2 anyways.

    GRACoL2006_Coated1 is characterization data IDEAlliance released and is based on the new G7 method of setting up a press. This G7 method tries to aim for defined visual densities and/or L* values throughout the scale using defined CMY percentages and defined K percentages (hence the G in G7 means gray, and the NPDC's aka Neutral Print Density Curves for CMY and K. The 7 in G7 stands for the seven solids defined in Lab that need to be matched within tolerance: C,M,Y,K,CM,MY,CY. This differs to the international standard's implementation in Europe, which defines specific densities (but also like G7 says that Lab values are more important, so they actually aren't really different here) and specific TVI aims (where the two really do differ, because G7 says that gray balance is more important than TVI and the international standard says TVI is more important I think).

    I made an Excel calculator that I used to fix my existing plate curves to match GRACoL2006_Coated1v2 and the pressmen are able to match the GRACoL2006_Coated1v2 proof on press. I tried to attach the Excel document (made on Mac Excel) but was not allowed to attach an .xls or .zip file (would like to know what I can attach then?!), so I can send it to you personally if you'd like. It will show the TVI differences between GRACoL2006_Coated1v2 and ISOcoatedv2 (both official IC profiles), and can also see how close the solids, overprints, and paper are between the two. I got the Lab numbers and did the calculations based on instructions and math found on Bruce Lindbloom's (color scientist) website (which I did another version based on Don Hutcheson's - current chair of GRACoL - math and both were in agreement with each other as far as TVI was concerned). The crux of the matter is that GRACoL2006_Coated1v2 is about 2-3% higher in TVI in the midtone in all separations than ISOcoated1v2. Enough of a difference to just tell a visual difference, but that's about it. With only this difference, it seems it would have been better to just adopt ISOcoated's NPDCs than make new ones that tried to match TR001 more (which matching TR001 makes old SWOP images look "natural" when printed on GRACoL2006_Coated1v2, but seems to have added confusion because we still don't have one universal characterization data/profile for each paper type where we could. If you have a press run with linear plates and you got to gray balance, use the NPDC chart on the 5th sheet in the Excel doc to get TVI changes needed. If you have an existing ICC profile of your press/paper/ink combo and have close paper and solids to the standard already, then you should be able to use the TVI calculator for individual TVI for each color (sheets 1-4 in Excel doc), use the 50 TVI change it recommends and average the 25 and 75 changes recommended to make them the same, change your plate TVI by that amount and smooth the curve, and you're good to go. I can't say it will definitely get you there, but my calculator has not only helped me, but also another person used it successfully to implement GRACoL2006_Coated1v2 at their site.

    To get Lab values to put into the Excel calculator, download the official profile GRACoL2006_Coated1v2 and/or ISOcoatedv2 and in Photoshop's color settings, choose the official profile as the CMYK profile and set rendering intent to Absolute Colorimetric. in the Info palette, set Seconde Readout to Lab Color. Then (using the downloaded "LabDotGainCalculator2.tif" from brucelindbloom.com or self-made tint blocks in 5% increments for each color) take the Lab readings, which you'll plug into the Excel calculator.

    BTW this can all be done faster and more precisely with IDEAlink Curve software from IDEAlliance, so I've given this as the free option because I did the research and built it and it's worked for me.

    As to your question, let's say we had one universal ICC profile for each paper, or two profiles for each paper, depending on the specification used (GRACoL2006_Coated1v2 or ISOcoatedv2). We know when we make plates that each platesetter/plate combo may need it's own calibration curve to make the plate linear (50 in file = 50 on plate), and we also know we need a bump curve to make the press print to the specification chosen (GRACoL2006_Coated1v2 or ISOcoatedv2). So no matter what, if plating files for one press or multiple presses, you'll need a calibration curve to make the plates linear in addition to a bump curve for each separation to match the specification. No way around it. I may need to increase my 50 to 54 to get linear plates while another platesetter may only need to move 50 to 52 and another platesetter may not need a calibration curve. Also, after getting linear plates, one press may need a 5% bump to get to specification aim TVI on press and another may need more or less, so I just can't see ever getting around this. Believe me, I have wondered the same thing as you before, but this is what I saw when looking at the situation.

    FYI, GRACoL2006_Coated1v2 we use for one customer who constantly approves the proof then likes to "paint" on press, and us using the latest PANTONE color bridge CMYK numbers and official GRACoL2006_Coated1v2 profile for our proof, and matching that proof on press, has not stopped them from painting on press.

    Don

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    • #3
      Re: I have a dream!?

      Thanks Don for your input, it has helped me understand the approach to profiling better, did you have some time to kill when writing your post? I think with litho offset where not far off the mark using the "out of the box" ISO standard from GMG. What I am not sure on is the standards for flexo & gravure. In my experience gravure printing characteristics are nothing below 2% dot as can't hold that on cylinder, dot gain about the same as litho offset & tendency towards a stronger cyan?. Flexo again minimum dot issues as can't hold small dot on flexo plate, dot gain can can be very high depending on age of press & substrate printed on, black prints weak?.

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      • #4
        Re: I have a dream!?

        If you have all those types of printing you're doing, I would look at either G7 method and make your own profiles (if in U.S.) or ISO 12647 and use ICC profiles from eci.org (if you don't want to use G7, which is understandable since you would have to make your own profiles and not be able to use "standard" profiles).

        I type fast, plus I wanted to let you know of the options.

        Don

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        • #5
          Re: I have a dream!?

          > {quote:title=Chief_1975 wrote:}{quote}
          > did you have some time to kill when writing your post?

          Don has gained world wide fame and is recognized for his willingness to help others and provide knowledgeable replies. He is a valued asset for PrintPlanet !! His detailed posts reflect a true commitment to helping and sharing with his peers. He must work a 28 hour day

          Thanks Don!!


          Regards,
          Dave M.

          Comment


          • #6
            Re: I have a dream!?

            Dave,

            "Don has gained world wide fame" - I think that came about the time I got in trouble for "bashing" a company and Inside Print Radio talked about the problem, correct?

            "and is recognized for his willingness to help others and provide knowledgeable replies. He is a valued asset for PrintPlanet !! His detailed posts reflect a true commitment to helping and sharing with his peers." - I can't think of a greater compliment than yours Dave. I don't think I've ever received this great of a compliment (although I lose track of compliments because I usually take them with a grain of salt. I like doing what I do in helping others and that's enough for me, although I can't say I don't like compliments - I do. Thank you.

            "He must work a 28 hour day" - I've had more mental breakdowns in this business than I ever had before getting into it, and yes, there are times I have stayed awake at nights building my own calculator, testing stuff at home, etc. Nowadays, since I'm to the point of understanding as much as I do and knowing what I can expect in (almost) any situation, I rest pretty good after work and don't stress too much while I'm here.

            "Thanks Don!!

            Regards,
            Dave M."

            Thank you again for your kind remarks Dave, and I will continue to help when I can. Besides the color management stuff, I can't say I've had much to contribute in a while, since most of the problems I used to encounter in the old days have been taken care of by updates to programs (for the most part, except color management in Quark, but I'm in a good mood and don't want to do anything to stop that, so we'll stop before we get into a conversation about Quark 7 - which I beta tested and gave feedback that still has not been listened to).

            Don

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            • #7
              Re: I have a dream!?

              > {quote:title=disbellj wrote:}{quote}

              > I type fast, >
              > Don

              Rock n Roll Don!

              Comment


              • #8
                Re: I have a dream!?

                ""Don has gained world wide fame" - I think that came about the time I got in trouble for "bashing" a company and Inside Print Radio talked about the problem, correct? "

                Dave, sorry for bringing this up. Uncalled for I know. I actually really do like my rip from AWS better than about anything I've used. It's just the lack of support (although paid for) and some things that have gotten broken by upgrades and never fixed by AWS, and the fact that I can't make type changes with the workflow that we bought (although can if we upgrade and pay more for Neo) that I have problems with the company. If these things got fixed, I'd have no qualms. I doubt they'll get fixed though, so that's why we no longer pay for support. Years of support and some things never got fixed.

                Don

                Comment


                • #9
                  Re: I have a dream!?

                  Rock on Vincent!

                  Don

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