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Re: [Digital BW] Optical Brightening Agents - OBAs

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  • Ernst Dinkla
    ... Paul, there are possibly ten or more there that tested bad on paper white shifts while the inks did better. The HP Pro Satin is an RC paper tested badly
    Message 1 of 9 , Mar 1, 2012
      On 02/29/2012 11:42 PM, Paul wrote:

      > Test prints using very good inks from Jon Cone and HP had some bad
      > Conservation Display Ratings in the Arrdenburg-Imaging
      > (http://www.aardenburg-imaging.com) fade tests that had nothing to do
      > with the pigments -- carbon sepia and Vivera. But the OBA burnout
      > triggered the end point on the Conservation Display Rating even thought
      > the pigments were not fading. That is, the images' overall appearance
      > had changed noticeably -- not good. The poor papers that did this were
      > Alise BW and HP Pro Satin. See http://www.aardenburg-imaging.com for the
      > test reports.
      >
      > Paul
      > www.PaulRoark.com

      Paul,

      there are possibly ten or more there that tested bad on paper white
      shifts while the inks did better.

      The HP Pro Satin is an RC paper tested badly but for example Canon
      Heavyweight Satin, also an RC paper, tested far better at Aardenburg.
      The quality of the OBA must play a role and where they are located in
      the paper. For example in an RC paper in the paper base itself between
      the polyethylene barriers the gas fading of OBAs could be reduced.

      Ten days ago I went through Aardenburg test results again to check paper
      white shifts and mentioned some observations on the Wide_Inkjet_Printers
      list. Here I repeat them:

      The use of protective coatings, Hahnemuhle, Premier, does wonders to
      reduce paper white shifts of OBA papers next to the protection of the
      inks. Check some tests at Aardenburg where the same paper is used with
      and without. My view is that gas like oxygen-ozone is blocked by the
      sprayed varnish.

      The printer applied gloss enhancers worry me a bit, it looks like the
      paper white shift
      is increased with gloss enhancers, MIS glop the most. Fiber/Baryta
      papers more than RC papers. Check two tests of Ilford Gold Fibre Silk
      with and without Glop. The test samples you mentioned should be seen in
      that light too. If Glop is in the inks too as an ink medium I wonder
      whether it influences MIS ink test results as well when applied on OBA
      papers that show paper white shifts more with Glop.

      I have some guesses what could be the reason for the paper white shift
      with gloss enhancer:
      * the gloss enhancer itself changes color
      * the gloss enhancer affects the OBAs. In literature I see glycol,
      glycerol and PVA mentioned as additions to OBA dyes for different
      reasons, one of them to increase the fluorescent effect. I wonder at
      what cost. The three are normal ingredients in ink medium.
      * the gloss enhancer changes the coating structure so gas fading of
      the OBA dyes can happen faster.

      I have to dig deeper in Aardenburg results, maybe something can be
      deducted there. More tests to separate possible causes are needed.


      BTW, the Canson Infinity Baryta Photographique that is in many ways a
      clone of the IGFS shows more paper white shift than IGFS. Could be a
      different surface that is more permeable or a different OBA used. I go
      for the first cause. It was noticed before that the surface looked
      slightly different.

      Remains the fact that OBA content of whatever kind influences the color
      management and restricts the display conditions of prints if
      "metamerism" has to be avoided. For B&W too. It is still a sound advice
      to avoid the high OBA content papers and go for papers with good, normal
      whitening agents like Baryte and TiO2. Just enough OBA to neutralise or
      brighten the last type of papers a bit is then a wise compromise.

      --
      met vriendelijke groeten, Ernst
      Shareware too:
      330+ paper white spectral plots:
      http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
    • Seth Rossman
      ... a pulp suspension with a filler composition comprising finely divided optically brightened plastic fibres,.... There we go. We are headed to
      Message 2 of 9 , Mar 1, 2012
        "... a pulp suspension with a filler composition comprising finely
        divided optically brightened plastic fibres,...." There we go. We are
        headed to polyester/cotton papers that are wash-and-wear! Sorry, I
        couldn't resist.

        Two things from Paul and Ernst bring up are worrisome.

        First, PVA's are generally considered a very stable adhesive in the
        conservation and museum community. If they are now in question it opens
        a whole new area--beyond photography.

        Second, there are plastics and there are plastics. Any that give off
        "plasticizers" will be an issue.

        Seth
      • Ernst Dinkla
        ... In relation with OBA the PVA is just one of the possible causes, I did not mention water next to the glycol and glycerol, there are also wetting agents etc
        Message 3 of 9 , Mar 1, 2012
          On 03/01/2012 12:29 PM, Seth Rossman wrote:

          > First, PVA's are generally considered a very stable adhesive in the
          > conservation and museum community. If they are now in question it opens
          > a whole new area--beyond photography.
          >
          > Second, there are plastics and there are plastics. Any that give off
          > "plasticizers" will be an issue.

          In relation with OBA the PVA is just one of the possible causes, I did
          not mention water next to the glycol and glycerol, there are also
          wetting agents etc in ink medium. All of the speculative as I do not
          have a clue. PVAs are quite inert as I understand it like gelatines are.
          OBAs will be the first problem in conservation anywhere, what other
          chemicals bring to that problem is the next question.

          Polyethylene is usually the plastic associated with Photo - RC papers.
          Its flexiblilty depends mainly on the polymer structure, high density
          quality is the flexible one, low density is used for large blow molded
          tanks etc. Plasticizers are more used for PVC/Vinyl/Cellulose Acetate
          plastics if I recall it correctly. Degradation of polyethylene outdoors
          is caused mainly by UV rays. Problems with RC papers in the past like
          cracking, loss of the bond to the paper base, were caused by certain
          types of TiO2 whitening agents mixed in the polyethylene front barrier,
          the back layer was usually transparent and remained unaffected. Today's
          RC papers are much different but should be tested on those aspects in
          relation to the colorants longevity. There is not much sense in testing
          beyond the colorants lifetime like there is no sense in testing the
          colorants beyond the paper's structural lifetime.

          --
          Met vriendelijke groeten, Ernst

          Shareware now:
          Dinkla Gallery Canvas Wrap Actions for Photoshop

          http://www.pigment-print.com/dinklacanvaswraps/index.htm

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          | www.pigment-print.com |
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        • Paul
          ... The OBAs are dyes, which seem to react more strongly to sprays. The Claria dyes also have much better light (and gas?) fastness when a protective spray is
          Message 4 of 9 , Mar 1, 2012
            Ernst Dinkla <e.dinkla@...> wrote:

            > ...
            > The use of protective coatings, Hahnemuhle, Premier, does wonders to
            > reduce paper white shifts of OBA papers ...

            The OBAs are dyes, which seem to react more strongly to sprays. The Claria dyes also have much better light (and gas?) fastness when a protective spray is used. The black only Claria ends prints have a lightfastness that is close to UltraChrome (color) neutral patch performance.

            > ... My view is that gas like oxygen-ozone is blocked by the
            > sprayed varnish.

            At some point I'd like to test the Lascaux Fixativ spray (no UV blocker) and the Premier spray (with UV blocker) to see how the results compare. Some years ago when Livick was doing a lot of testing, I believe a combination of Lascaux first (it soaks in better) and then a UV blocker appeared to extend print life the longest.




            >
            > The printer applied gloss enhancers worry me a bit,
            > it looks like the paper white shift
            > is increased with gloss enhancers, MIS glop the most. ...

            > In literature I see glycol,
            > glycerol and PVA mentioned as additions to OBA dyes for different
            > reasons, one of them to increase the fluorescent effect. I wonder at
            > what cost. The three are normal ingredients in ink medium.
            > * the gloss enhancer changes the coating structure so gas fading of
            > the OBA dyes can happen faster.


            I looked at some Aardenburg-Imaging <http://www.aardenburg-imaging.com/acceleratedagingtests.html> results and tried to compare the Epson Gloss Optimizer (R800/1800) results with the UltraChrome results on the same glossy papers (Premium Glossy and Luster). I can't tell from the materials whether the Epson GO was turned on or off in those tests; I have assumed the GO is being used. The Epson GO uses a lot (25 - 30%) of glycerol. (See http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&oid=30501&infoType=MSDS). The R800/1800 overall has better fade numbers than the UC printers. But that could have been due to no light pigments or the additional ones they use (although the yellows are probably the same and it does better there too). With respect to the paper white, in the tests where Premium Glossy is used, the UC printer had a very slight advantage. With the Luster, the R800/1800 had the advantage. (But there it was roll paper v. sheet, so there could have been a relevant variable there.) At any rate, I'd say, assuming the GO was being used, there was not serious detriment to the inks from the GO and its high glycerol content.



            > ... It is still a sound advice to avoid the high OBA content papers ...


            Although it's interesting that natural papers also shift color -- bleaching whiter. So, the best paper may have just enough OBAs in it so the effects balance each other. Some H. Photo Rag tests suggest that is what Hahnemuhle succeeded in doing.

            > and go for papers with good, normal whitening agents like Baryte

            Do the baryta papers have a polyethylene barrier in them?


            > and TiO2.


            Note the extent of bleaching of Arches watercolor papers and Epson Hot Press natural. It seems like neither of these papers is bleached in processing as much as most of the others. I experimented with bleaching Arches with H2O2. It did bleach the paper somewhat, but peroxide is also a mild acid, so it affected the pH -- not recommended.

            I also have tried a TiO2 wash with Arches. That looks like it might be worth a bit more effort. It's too early for any conclusions, but it did increase the whiteness. Arches Hot Press has a bit of reflective sheen that makes the paper relatively brighter near where the light is reflecting off the paper. With the TiO2, that sheen is reduce, with the effect that "off axis" brightness is increased noticeably. Particularly where spotlights are use on it, this might significantly improve the brightness of the paper and the apparent dynamic range of the image.

            Paul
            www.PaulRoark.com
          • Ernst Dinkla
            ... I asked Mark in the dpreview forum whether the paper white was measured including gloss enhancer when avialable in the inkset. He was positive on that. If
            Message 5 of 9 , Mar 1, 2012
              On 03/01/2012 05:56 PM, Paul wrote:


              > I looked at some Aardenburg-Imaging
              > <http://www.aardenburg-imaging.com/acceleratedagingtests.html> results
              > and tried to compare the Epson Gloss Optimizer (R800/1800) results with
              > the UltraChrome results on the same glossy papers (Premium Glossy and
              > Luster). I can't tell from the materials whether the Epson GO was turned
              > on or off in those tests; I have assumed the GO is being used. The Epson
              > GO uses a lot (25 - 30%) of glycerol. (See
              > http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&oid=30501&infoType=MSDS
              > <http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&oid=30501&infoType=MSDS>).
              > The R800/1800 overall has better fade numbers than the UC printers. But
              > that could have been due to no light pigments or the additional ones
              > they use (although the yellows are probably the same and it does better
              > there too). With respect to the paper white, in the tests where Premium
              > Glossy is used, the UC printer had a very slight advantage. With the
              > Luster, the R800/1800 had the advantage. (But there it was roll paper v.
              > sheet, so there could have been a relevant variable there.) At any rate,
              > I'd say, assuming the GO was being used, there was not serious detriment
              > to the inks from the GO and its high glycerol content.


              I asked Mark in the dpreview forum whether the paper white was measured
              including gloss enhancer when avialable in the inkset. He was positive
              on that. If in the inkset and gloss paper used the paper white is
              measured with the gloss enhancer applied.
              In that case tests with Epson R800, R1800, Z3100, Z3200 printers and
              third party inks for mentioned printers should be checked.

              I went along the Epson Premium Luster tests with said printers and I see
              a slight negative change on the paper white shifts if compared to
              printers without a gloss enhancer (Epson 4800, Epson 2200), at 30
              Megalux Hours they all are at 100 but at 60 MH the change sets in. Of
              two tests that went to 240 MH, the Epson 4800 bare paper white was at
              71,1 and the R1800 with GE at 51,6.

              The same done for Ilford Gold Fibre Silk, less tests there done above 80
              MH but gloss enhancer samples at 80 MH show more paper white shift than
              bare paper samples show. The Z3100 test goes up to 180 MH and shows more
              shift 83,9 than a bare 200 MH IGFS test showed with 87,1. At 160 MH
              there is even a dip to 77,7 which I attribute to a false measurement as
              it went up again after that period.

              Not too many samples tested with GE applied but I do not see one that
              goes in the other direction.

              The contrast with samples sprayed with a protective varnish is even more
              pronounced so we should forget that a gloss enhancer has a similar
              quality, it is rather the opposite.


              --
              Met vriendelijke groeten, Ernst

              Shareware now:
              Dinkla Gallery Canvas Wrap Actions for Photoshop

              http://www.pigment-print.com/dinklacanvaswraps/index.htm

              | Dinkla Grafische Techniek |
              | www.pigment-print.com |
              | ( unvollendet ) |
            • Paul
              ... The variance among the tests is surprising. Looking just at the Epson Premium Luster paper white samples at 100 Mlux-hours, the I* Color for the printers
              Message 6 of 9 , Mar 1, 2012
                Ernst Dinkla <e.dinkla@...> wrote:
                >
                ...
                > In that case tests with Epson R800, R1800, Z3100, Z3200 printers and
                > third party inks for mentioned printers should be checked.
                >
                > I went along the Epson Premium Luster tests with said printers
                > and I see
                > a slight negative change on the paper white shifts if compared to
                > printers without a gloss enhancer (Epson 4800, Epson 2200), ...


                The variance among the tests is surprising. Looking just at the Epson Premium Luster paper white samples at 100 Mlux-hours, the I* Color for the printers with no gloss optimizer in them were
                92.9 for a 2200 (AaI_20080309_SN002Lf.pdf),
                88.5 for a 4800 (AaI_20071218_SN009Lf.pdf), and
                79.7 for a 3800 (AaI_20090510_SN001Lf.pdf).


                The 1800 with OEM inks had an I* Color of 82.2 (AaI_20071008_SN013Lf.pdf), and the 1800 with MIS glop in it had an I* Color of 83.8. (AaI_20071008_SN007Lf.pdf)

                Given the variance we see in the bare paper whites, I'm not sure we can conclude much about the gloss optimizers.

                In retrospect, I think a critical piece of information at the outset would be to know whether the OBAs are in the paper base or coating. If it is in the paper, protected by polyethylene, it's hard to see what impact gloss optimizer would have on them.

                Overall, however, the numbers you extracted from the data do tend to show more paper white change when gloss optimizer is used.


                > The contrast with samples sprayed with a protective varnish
                > is even more pronounced so we should forget that a gloss
                > enhancer has a similar quality, it is rather the opposite.

                With the sprays, the issue I'd be curious about is the UV blocking effect v. some effect of slowing down oxidation.


                Paul
                www.PaulRoark.com
              • Ernst Dinkla
                ... Alright, that replaces part of my worries from the GE applied to the Luster consistency :-) I still think we should be aware that there might be something
                Message 7 of 9 , Mar 2, 2012
                  On 03/02/2012 05:11 AM, Paul wrote:

                  > Given the variance we see in the bare paper whites, I'm not sure we can
                  > conclude much about the gloss optimizers.

                  Alright, that replaces part of my worries from the GE applied to the
                  Luster consistency :-)
                  I still think we should be aware that there might be something going on
                  with the GE, at the end of the year more test information will be
                  available. Some tests were done on the same paper batch. When I read
                  that people dedicate an old wide format to apply an extra layer of gloss
                  enhancer I think they should be sure that the GE used does not degrade
                  the prints on the long run.

                  With the HP Z gloss enhancer there are other issues like the bronzing
                  that is still visible on more gloss papers. The Premier and HM
                  protective coats do their job but I like to work with bulk water based
                  dispersions. The Premiere Art Eco could be used for papers too I
                  understand but I suspect the coating is not that gas tight.


                  --
                  Met vriendelijke groeten, Ernst

                  Shareware now:
                  Dinkla Gallery Canvas Wrap Actions for Photoshop

                  http://www.pigment-print.com/dinklacanvaswraps/index.htm

                  | Dinkla Grafische Techniek |
                  | www.pigment-print.com |
                  | ( unvollendet ) |
                • John
                  Ernst: It doesn t take much of a protective coat on the microporous ink jet media to protect against oxidation. Any sealant is better than leaving it open to
                  Message 8 of 9 , Mar 2, 2012
                    Ernst:
                    It doesn't take much of a protective coat on the microporous ink jet media to protect against oxidation. Any sealant is better than leaving it open to the air and pollutants in the short term. In the long term you do want a sealant that does not discolor (patina) in the long run, like many older lacquers and varnishes.

                    The aquas PVAs have a good reputation in this regard from the 1950's.

                    John Nollendorfs

                    --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Ernst Dinkla <e.dinkla@...> wrote:

                    > With the HP Z gloss enhancer there are other issues like the bronzing
                    > that is still visible on more gloss papers. The Premier and HM
                    > protective coats do their job but I like to work with bulk water based
                    > dispersions. The Premiere Art Eco could be used for papers too I
                    > understand but I suspect the coating is not that gas tight.
                    >
                    >
                    > --
                    > Met vriendelijke groeten, Ernst
                    >
                    > Shareware now:
                    > Dinkla Gallery Canvas Wrap Actions for Photoshop
                    >
                    > http://www.pigment-print.com/dinklacanvaswraps/index.htm
                    >
                    > | Dinkla Grafische Techniek |
                    > | www.pigment-print.com |
                    > | ( unvollendet ) |
                    >
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