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Paper mills adding more and more artificial brighters in the papers??

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  • Paper mills adding more and more artificial brighters in the papers??

    I have heard from a reliable source that the mills are adding more and more artificial brighteners in the paper, which inhibits the reflective properties in the paper-- especially in the cyan (I think)-- so the images-- especially in neutral colors, esp. grays-- go violet under warm lighting (while they look fine in 5000 kelvins).

    So if this is true, what happens to printers round the world as standard printig conditions are 5000K, viewing booths are 5000K?

  • #2
    Re: Paper mills adding more and more artificial brighters in the papers??

    The color temperature of the light (degrees Kelvin) is unrelated to the UV content of the light.
    The increased use of optical brightners is a big issue since there are real no standards nor device measurement metrics. As Larry Warter of Fuji has said: "Highly brightened Grade 1 papers make color management virtually impossible unless you proof on the production stock"


    best, gordo

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    • #3
      Re: Paper mills adding more and more artificial brighters in the papers??

      Hi Gordon, thanks for your response. So with added optical brighteners in the paper coating, and "Highly brightened Grade 1 papers make color management virtually impossible unless you proof on the production stock", what happens to the digital proofing world?

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      • #4
        Re: Paper mills adding more and more artificial brighters in the papers??

        There are a few of options in regards to the predominance of brightening agents in papers....

        1) Use UVcut filtration on both the measuring instrument and the lighting conditions to prevent the excitation of brightening agents. Possible, but perhaps impractical, as it would require all lighting conditions have their UV source cut.

        2) Select papers, both proof and production, that contain no brightening agents, or at least limited agents and similar amounts between proof and production stocks. Both options are difficult, but possible. However, production stocks change frequently making this a moving target Another option with paper is to use the actual production stock ala the Whole Proof, which coats printing stocks for use with inkjet devices.

        3) Use software compensation. ProfileMaker and the Argyl CMS (Heidelberg as well?) both offer the option to correct for brightening agents present in measurement data. These options rely on spectral, UV included measurement data. ProfileMaker limits this correction to the perceptual rendering intent only. Argyll's limitation is its command line "interface". Ideally both the proofing and the simulation profile would have the brightener correction made to them, and with standard measurement data like the SWOP, Gracol and Fogra data sets only containing colorimetric values, this may have limited usefulness.

        Given the drive for cheaper/whiter papers, I don't think brightening agents will be going away. I think the best hope to lessen this issue relies in the use of intelligent software correction of the brightening agent's effects. and a stricter regulation of UV content of lighting conditions. Drafts of ISO 13655 and ISO 3664 are attempting to lessen the issues to some degree.

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        • #5
          Re: Paper mills adding more and more artificial brighters in the papers??

          It's a significant issue. I believe that according to the folks in the CRACoL group that the use of optical brightners has resulting in the fact that no press paper meets the ISO spec.
          Some proofing vendors indicate which of their substrates contain brightners and which do not, s that you can better align the proof media to the paper that will be going on press.
          Another wrinkle is that some press inks contain OBs.
          The pic below shows, on the left under 5000, one vendor's proofing media, Press process inks, the Pantone Goe, and old PMS swatchbooks. On the right you can see them under black light. Note the different amounts of OBs in the proofing paper, the fact that the yellow process ink contains OBs, and that the Goe swatchbook has significantly more OBs than the PMS book.

          !http://www.bytephoto.com/photopost/data/500/10692UV.jpg!

          You can get a qualitative representation of the level of OB in your media by looking at them with a black light. These bulbs are cheap - about $10, buy the fluorescent type rather than the incandescent.


          - gordo

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          • #6
            Re: Paper mills adding more and more artificial brighters in the papers??

            Hey Gordo,

            Do not forget that black lights also make Jimi Hendrix posters look cool!

            Regards,

            Mark
            Mark Tonkovich
            Heidelberg USA

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            • #7
              Re: Paper mills adding more and more artificial brighters in the papers??

              What's that old saying..."if you remember the sixties you didn't experience it"
              Like, cool man, get a haircut and maybe we''ll do lunch sometime at Alice's Restaurant. LOL

              Anyway, shining a black light on the black art of prepress can't be a bad idea. :-)

              - gordo

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              • #8
                Re: Paper mills adding more and more artificial brighters in the papers??

                If one has access to a spectro that measures both UV included and UV excluded measurement, this would allow a more quatifiable representation of the effect flourescence (at least of the measureing instrument, if not our eyes). Although this would give more of an idea of how the effects will play out for color management, its not nearly as groovy or psyhcodelic as a black light.

                Edited by: Michael Eddington on Apr 8, 2008 8:06 AM

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                • #9
                  Re: Paper mills adding more and more artificial brighters in the papers??

                  Gordo,

                  It looks like CGS ORIS paper swatchbook.

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                  • #10
                    Re: Paper mills adding more and more artificial brighters in the papers??

                    i would agree that adding brighteners would be a major problem when it comes to color management.

                    as I have never seen a brighter that was not artificial, well, bring on the all natural, organic recyclable brighteners i guess, maybe they will be better.

                    Edited by: Michael Jahn on Apr 8, 2008 8:44 PM
                    Michael Jahn - Slightly used PDF Evangelist
                    Simi Valley California

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                    • #11
                      Re: Paper mills adding more and more artificial brighters in the papers??

                      They definitely have added more optical brighteners to the paper. I work for a lightbooth manufacturer and we had to remove over 90% of our UV energy from our 5000K lamp phosphor blend about 5 years ago. Everyone was complaining that all their images were glowing. It doesn't have to do with the correlated color temperature of the light source. It is strictly a function of the energy in the 300-400 nm range. Most commercial lamps have very little to no energy down there nowadays.
                      Peace.

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