OBAs

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    Topic: OBAs Read 193 Times
  • Daniel Koretz
    Daniel Koretz
    Participant
    Posts: 19
    Papers & Media
    on: August 22, 2020 at 10:59 am

    To follow up on the earlier postings about baryta papers:

    The discontinuance of the original Canon Baryta Photographique has led me to test a bunch of other baryta papers, and that brought me back again to the question of OBAs. Canson listed the original Baryta Photographique as “very low” in OBAs. The barytas with no OBAs that I have tested so far, such as Hahnemuehle Fine Art Baryta Satin, are noticeably warmer, which I don’t particularly like. (I haven’t yet tested Breathing Color River Stone Satin Rag, which has no OBAs. I have some en route now.) Hahnemuehle also produces two barytas that they say have “moderate” OBAs, Baryta FB and Fine Art Baryta, and Canson produces one, Baryta Prestige, which seems to have considerably more than Baryta Photographique.

    My question is what tests actually show about the problem of deterioration of OBAs. I have read that they are more stable when embedded in a baryta layer, but I haven’t seen any backup for that claim. How long does visible deterioration take? And to what extend is the deterioration nonuniform? A uniform deterioration of OBAs would simply make the paper gradually look like it had none.

    I’m guessing that since both Hahnemuehle and Canson use moderate OBAs in some of their fine art papers, the common concern about them is overblown, but I would like more to go on before choosing a new paper for prints for sale.

    Thanks for any guidance.

    Mark D Segal
    Mark D Segal
    Participant
    Posts: 230
    Re: OBAs
    Reply #1 on: August 22, 2020 at 11:02 am

    The best resource for information on the real impacts of OBA fading is Aardenburg Imaging. https://www.aardenburg-imaging.com/

    Mark D Segal
    Author: Scanning Workflows with SilverFast 8, SilverFast HDR, Adobe Photoshop Lightroom and Adobe Photoshop, published by LaserSoft Imaging AG
    https://www.silverfast.com/downloads/92ed080ac1ae274ea6aeed756a504f7a/en.html

    Daniel Koretz
    Daniel Koretz
    Participant
    Posts: 19
    Re: OBAs
    Reply #2 on: August 22, 2020 at 1:36 pm

    Mark,

    Thanks. Following your post, I found a good article on Aardenburg. However, it doesn’t address the assertion that OBAs degrade more slowly when embedded in a coating. A Canson rep sent me this some time ago:

    unlike porous paper, OBAs present in clay or a resin coating are far more protected and stable. OBAs typically fade in paper within 7-35 years depending on the amount of light exposure.

    He didn’t clarify which type of paper the 7-35 year estimate applies.

    Dan

    Dan

    Andrew Rodney
    Andrew Rodney
    Participant
    Posts: 56
    Re: OBAs
    Reply #3 on: August 22, 2020 at 3:31 pm

    Best thing to do, if you’re concerned about the archivability of your prints, how differing illuminates affect viewing: totally avoid OBAs.

    Author: “Color Management for Photographers”

    Mark D Segal
    Mark D Segal
    Participant
    Posts: 230
    Re: OBAs
    Reply #4 on: August 22, 2020 at 5:37 pm

    Andrew is right about that. There are good papers in both PK and MK categories that do not use OBAs/FBAs.

    But if for some reason you must use a paper with low OBA content, I have been informed by one major high quality manufacturer that the safest place to put them is in the substrate, and then in only very modest amounts.

    Mark D Segal
    Author: Scanning Workflows with SilverFast 8, SilverFast HDR, Adobe Photoshop Lightroom and Adobe Photoshop, published by LaserSoft Imaging AG
    https://www.silverfast.com/downloads/92ed080ac1ae274ea6aeed756a504f7a/en.html

    Daniel Koretz
    Daniel Koretz
    Participant
    Posts: 19
    Re: OBAs
    Reply #5 on: August 22, 2020 at 7:54 pm

    <p>”But if for some reason you must use a paper with low OBA content, I have been informed by one major high quality manufacturer that the safest place to put them is in the substrate, and then in only very modest amounts.”</p>
    <p>That seems to be what Canson did with the original Baryta Photographique, which was my most-used paper until it was discontinued, as well as the replacement Baryta Photographique II, the surface of which I don’t love.</p>
    <p>Andrew’s advice is clearly the safest path, but I have always liked cold-tone papers since I first did wet-darkroom printing many decades ago, so I’ve been searching for relatively cold-tone OBA-free baryta papers to replace Baryta Photographique. I have one or two more to test, but so far, no luck: everything I’ve tried is either warmer than I like or is produced with substantial OBAs. I’m increasingly thinking about using Canson Platine Fibre Rag as a replacement. Even though it’s not a baryta paper, it’s very close to the original Baryta Photographique in appearance. Even though it has a CIE whiteness of 89, its appearance is colder than some baryta papers that nominally have higher whiteness values.</p>
    <p>I’m still holding out hope for Breathing Color River Stone Satin Rag. Should arrive within a few days.</p>



    Guest
    Posts: 2
    Re: OBAs
    Reply #6 on: August 29, 2020 at 2:57 pm

    Mark / Andrew –  at a high level,  I would have given a similar answer on OBAs, but when I look at the results from Wilhelm Research on the Epson Ultrachrome HD inkset that was published in February 2019:

    http://wilhelm-research.com/epson/WIR_Epson_SureColor_P600_Printer_2019-02-15.pdf

    On page 2 of their report they show the life on the OBA containing Epson Hot Press Bright and Cold Press Bright having better life than the Epson Hot Press Natural and Cold Press Natural papers, regardless of the test parameters.  All four are marketed as archival papers.  I have used all four papers for a number of years and other than the slightly warmer tones of the natural line, the two hot press papers and two cold press papers are physically quite similar (weight, surface finish, etc.) which has me wondering if the only difference can be found in the finishing process.  From a paper manufacturing standpoint, this would make a lot of sense; one base raw material can be turned in two different final products.

    Print life is apparently less straight forward than suggesting OBAs reduce print life.

    Any thoughts or insights here?

    Mark McCormick-Goodhart
    Mark McCormick-Goodhart
    Participant
    Posts: 4
    Re: OBAs
    Reply #7 on: September 7, 2020 at 8:51 pm

    On page 2 of their report they show the life on the OBA containing Epson Hot Press Bright and Cold Press Bright having better life than the Epson Hot Press Natural and Cold Press Natural papers, regardless of the test parameters.

    The WIR densitometric test method has a liberal allowance for media white discoloration, so OBA fading rarely if ever triggers the media white patch endpoint criterion in WIR testing. Yet media yellowing is often one of the first changes to be noticed as prints and photographs age. Also, with pigmented ink sets such as Canon Lucia Pro, Epson K3 or HD, and other pigmented ink sets, the yellow colorant tends to be the least fade resistant ink, so this leaves the yellow patch in the 9 patch WIR test target as the next likely patch to reach its specified failure point in the WIR test (i.e. 35% blue density loss in the yellow patch). Because a more yellowish appearance to the printed image caused by OBA burnout counteracts to some degree the measured loss of yellow in the yellow test patch, OBA fading works in favor of propping up yellow patch density, which in turn results in a better WIR test score.  Unfortunately, this increased yellowing also works at a decided disadvantage to other real world colors like pastel blues. cyans, very light grays, etc., which are not part of the WIR test chart.  Hence, WIR testing tends to simplistically rate papers with OBA content more favorably than they really deserve. It’s a limitation of the longstanding WIR densitometric test method.

    In Aardenburg testing, OBA fading and media whitepoint stability is scored very differently than in WIR testing.  Bright white media containing high, moderate, and even low OBA content never do better in test than their “natural white” OBA-free media counterparts. Typically, they perform significantly worse. Thus, choosing OBA-free media for archival printing purposes, is indeed the safest bet. Choosing media with OBAs existing only in the paper core and not in any of the coatings is the next safest choice. Regrettably, many folks don’t know how to select OBA-free or low OBA (in paper core only) papers, and the manufacturers really don’t want you to know how, either.

    kind regards,
    Mark

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    Daniel Koretz
    Daniel Koretz
    Participant
    Posts: 19
    Re: OBAs
    Reply #8 on: September 8, 2020 at 4:18 pm

    Mark,

    Thanks. This was both helpful and very interesting.

    Dan



    Guest
    Posts: 1
    Re: OBAs
    Reply #9 on: September 8, 2020 at 8:39 pm

    Thanks for the response Mark (I posted the question you answered (#6), but my login / password were not working so I signed up as a new account)).

    I had suspected that the Aardenburg test methodology was likely more rigorous that the WIR, so thank you for confirming this.  Your explanation makes sense as the fading of the OBA and fading of the yellow ink would seem to at least partially compensate for each other, but still, overall the quality of the print will have been compromised.

    Do you test for the physical longevity of the base and finish on the papers as well?  I seem to remember alpha cellulose breaks down more quickly than cotton fibres or is that a minor issue when compared to ink degradation?

     

     

    Mark McCormick-Goodhart
    Mark McCormick-Goodhart
    Participant
    Posts: 4
    Re: OBAs
    Reply #10 on: September 9, 2020 at 8:40 am

    Hello Manfred, thanks for signing in as a participant and for the feedback. It did cross my mind that you might be a manufacturer weighing in as “guest” in post #6, but no matter. Happy to try to explain to anyone, even folks with vested interests.

    I’m not too concerned about the stability of the paper base, even alpha cellulose papers. They are generally high quality papers with much more refined processing than cheap woodpulp newspaper stock, and the paper making industry as well as museums and archives have literally centuries of solid testing and research  concerning their long term stability. That said, the modern day microporous/nanoporous coatings used in nearly all aqueous inkjet printing do not have a long track record of use, and further thermal aging studies to look at both yellowing and physical integrity as they age is certainly of interest to me.

    Regrettably, the Aardenburg research model based on enduser participation and truly independent funding free of manufacturer influence has mostly run its course over the last decade, never generating enough support from the printmaking community to pursue any accelerated thermal aging or gas fading studies. What I can do is simply track the course of natural dark storage aging of test samples in our archive. Those studies are beginning to yield some interesting data now that samples are reaching a decade or more of time in storage. It’s slow and painstaking work, but it may eventually lead to some recommendations for wiser choice of media where archival prints are desired and for better care and handling of any inkjet prints in both museum and private collections.

    cheers,
    Mark

     

    Mark McCormick-Goodhart
    Mark McCormick-Goodhart
    Participant
    Posts: 4
    Re: OBAs
    Reply #11 on: September 9, 2020 at 8:50 am

    Hello Manfred, thanks for signing in as a participant and for the feedback. It did cross my mind that you might be a manufacturer weighing in as “guest” in post #6, but no matter. Happy to try to explain to anyone, even folks with vested interests.

    I’m not too concerned about the stability of the paper base, even alpha cellulose papers. They are generally high quality papers with much more refined processing than cheap woodpulp newspaper stock, and the paper making industry as well as museums and archives have literally centuries of solid testing and research  concerning their long term stability. That said, the modern day microporous/nanoporous coatings used in nearly all aqueous inkjet printing do not have a long track record of use, and further thermal aging studies to look at both yellowing and physical integrity as they age is certainly of interest to me.

    Regrettably, the Aardenburg research model based on enduser participation and truly independent funding free of manufacturer influence has mostly run its course over the last decade, never generating enough support from the printmaking community to pursue any accelerated thermal aging or gas fading studies. What I can do is simply track the course of natural dark storage aging of test samples in our archive. Those studies are beginning to yield some interesting data now that samples are reaching a decade or more of time in storage. It’s slow and painstaking work, but it may eventually lead to some recommendations for wiser choice of media where archival prints are desired and for better care and handling of any inkjet prints in both museum and private collections.

    cheers,
    Mark

    note: My first attempt to post this reply seemed to disappear after I edited one minor typo. If this repost ends up as a duplicate that I can’t remove, please accept my apologies.

     

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