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Author Topic: OBA free vs. RC resistance to UV  (Read 17849 times)

Tim Lookingbill

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Re: OBA free vs. RC resistance to UV
« Reply #20 on: August 29, 2015, 02:08:54 pm »

I have a friend whose comment back is, "I'll just reprint if there is a fading/color problem."

I've been saying that to myself reading through this entire thread.

But then I remembered the incredible looking wall sized window display signage at a new clinic built about two years ago and it seems to be holding up.

Check out the upper left two photos taken of this signage...

http://www.nbsignsanddesign.com/#Portfolio

Wonder what they do to preserve the look of these photos?
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MHMG

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Re: OBA free vs. RC resistance to UV
« Reply #21 on: August 29, 2015, 02:54:05 pm »

Interesting comment.  Do you know what the relative reactivity might be for barium sulfate versus TiO2?  Both are commonly used whitening agents though I believe TiO2 is less expensive on a bulk basis than barium sulfate.  It has been a lot of years since I studied this stuff in college and I know that some of the reactivity is dependent on the crystal structure of the compound.  I wouldn't wait around for manufacturers to reformulate OBA free papers since there are lots of users that just like the performance.  I have a friend whose comment back is, "I'll just reprint if there is a fading/color problem."

Barium Sulfate has never had the reactivity issue like TiO2, but it has also never been added to a PE layer in an RC paper in lieu of TiO2, so there may be other production/compatibility problems with that combination. As for manufacturers reformulating RC papers, two things come to mind. First, these papers exist already, but they are targeted to the proofing market not the Photo market. It's not difficult to leave OBAs out of the PE-TiO2 layer. Second, RC media were first introduced into the photofinishing market in the early 1970s in order to usher in the "1 hour photo" service era. All photos at that time were dye based systems with poor to moderate light fade resistance at best, so the weak link in terms of lightfastness on display was always the dye image itself. If the paper held up a little longer than the dyes on display that was really all that was needed from a manufacturer's perspective. The media didn't have to be a 100+ year archival support for a print on continuous display. The image itself would not look good well before that time had passed.  In contrast, today we have entered a new era of inkjet RC photographs where the latest OEM pigments are being printed on essentially the same PE-TiO2 technology of the 1980s. As such, the battleground for print longevity is shifting significantly to the quality of the media rather than the lightfastness of the colorants forming the image. None of this matters for the "I can always reprint" folks, but that's a one generation limit.  I doubt the next generation will easily be able to track down the original digital image file or always take the time and expense to have the fading original recopied and digitally restored, nor would that suffice for a signed piece of artwork. So, IMHO, print permanence still matters.

cheers,
Mark
http://www.aardenburg-imaging.com
« Last Edit: August 29, 2015, 05:37:19 pm by MHMG »
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Tim Lookingbill

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Re: OBA free vs. RC resistance to UV
« Reply #22 on: August 29, 2015, 07:52:21 pm »

None of this matters for the "I can always reprint" folks, but that's a one generation limit.  I doubt the next generation will easily be able to track down the original digital image file or always take the time and expense to have the fading original recopied and digitally restored, nor would that suffice for a signed piece of artwork. So, IMHO, print permanence still matters.

cheers,
Mark
http://www.aardenburg-imaging.com

I love prints. I like having something in my hands that I created through the photographic process.

But I'm not sure the next generation is going to appreciate the complexities and craftsmanship of paper and printmaking with regard to print longevity capabilities when there's now 1mm thin OLED displays to hang on the wall with far better dynamic range and color than a print on paper.

http://www.digitaltrends.com/home-theater/lg-display-55-inch-flat-oled-panel-sticks-to-wall-with-magnet/

If image viewing technology has advanced this far today, there's no telling what improvements will be around 40 years down the road.
« Last Edit: August 29, 2015, 07:53:58 pm by Tim Lookingbill »
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MHMG

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Re: OBA free vs. RC resistance to UV
« Reply #23 on: August 29, 2015, 08:17:28 pm »


But I'm not sure the next generation is going to appreciate the complexities and craftsmanship of paper and printmaking with regard to print longevity capabilities when there's now 1mm thin OLED displays to hang on the wall with far better dynamic range and color than a print on paper.


Each successive generation does indeed have its own preferred mode of representing the popular photographic images at the time. But one will still have to respect the craft of the earlier generation as the best possible voice for that generation. What would you rather own... the original albumen print (only one still in existence) of the Abraham Lincoln "Cracked plate" portrait taken by Alexander Gardner in the 19th Century (http://www.si.edu/Exhibitions/Details/Cracked-Plate-Photograph-of-Lincoln-5760), or a digital reproduction of this image displayed in full living color on your OLED display?  :)

I make prints. I make them with the unfailing belief that someone in the future will value them for what they are, irrespective of the incredible improvements in photography and image reproduction that are likely to occur in the future.

cheers,
Mark
http://www.aardenburg-imaging.com
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Alan Goldhammer

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Re: OBA free vs. RC resistance to UV
« Reply #24 on: August 30, 2015, 01:11:04 pm »

Barium Sulfate has never had the reactivity issue like TiO2, but it has also never been added to a PE layer in an RC paper in lieu of TiO2, so there may be other production/compatibility problems with that combination. As for manufacturers reformulating RC papers, two things come to mind. First, these papers exist already, but they are targeted to the proofing market not the Photo market. It's not difficult to leave OBAs out of the PE-TiO2 layer. Second, RC media were first introduced into the photofinishing market in the early 1970s in order to usher in the "1 hour photo" service era. All photos at that time were dye based systems with poor to moderate light fade resistance at best, so the weak link in terms of lightfastness on display was always the dye image itself. If the paper held up a little longer than the dyes on display that was really all that was needed from a manufacturer's perspective. The media didn't have to be a 100+ year archival support for a print on continuous display. The image itself would not look good well before that time had passed.  In contrast, today we have entered a new era of inkjet RC photographs where the latest OEM pigments are being printed on essentially the same PE-TiO2 technology of the 1980s. As such, the battleground for print longevity is shifting significantly to the quality of the media rather than the lightfastness of the colorants forming the image. None of this matters for the "I can always reprint" folks, but that's a one generation limit.  I doubt the next generation will easily be able to track down the original digital image file or always take the time and expense to have the fading original recopied and digitally restored, nor would that suffice for a signed piece of artwork. So, IMHO, print permanence still matters.

cheers,
Mark
http://www.aardenburg-imaging.com
I agree with you completely.  Maybe the paper manufacturers feel that they don't need to do much innovation as there are already enough choices out there in such a fragmented market.  I also think that TiO2 being a huge commodity chemical is a lot cheaper than bariums sulfate.
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pcm81

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Re: OBA free vs. RC resistance to UV
« Reply #25 on: August 30, 2015, 01:33:48 pm »

Thank you all for such wonderful and thought provoking replies. It is great to see so many, so knowledgeable, individuals sharing their technical knowledge for the benefit of others.

The replies in this thread brought up an interesting point, and that is: "overall reactivity of the paper".
I originally thought of OBAs as consumable material, but clearly they are much more than that, due to chemical reactions and follow-on degradation they cause.
We often pay attention to two major factors in our printing medium:
1. Acidity
2. OBA Content

But perhaps we need to replace the acidity criteria with the "reactivity" criteria.
Whether it is acid present in the paper or the staining due to burned out OBA, total chemical changes in printing medium need to be taken into consideration.

I think that "archival printers wet dream" would be a database of papers examining not just light fading data, but also presenting overall reactivity data. Essentially a chemical analysis projecting the final equilibrium state of the paper after OBAs burned out, and all other chemicals present in the paper completed their chemical dance.
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Alan Goldhammer

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Re: OBA free vs. RC resistance to UV
« Reply #26 on: August 30, 2015, 02:24:20 pm »

I think that "archival printers wet dream" would be a database of papers examining not just light fading data, but also presenting overall reactivity data. Essentially a chemical analysis projecting the final equilibrium state of the paper after OBAs burned out, and all other chemicals present in the paper completed their chemical dance.
You only need fading and color change data of the sort already posted on the Aardenburg website.  That type of study is relatively easy to complete whereas the one you describe is far more complicated.  And of course everything is dependent on the environmental conditions that the prints are stored/displayed. 
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Tim Lookingbill

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Re: OBA free vs. RC resistance to UV
« Reply #27 on: August 30, 2015, 07:00:15 pm »

I also think that TiO2 being a huge commodity chemical is a lot cheaper than bariums sulfate.

That explains why the giant tube of Titanium White acrylic paint for fine artists was always sold out at the art store. No fine art painter's palette could do without it going by all the books I read giving advice on what made the best artist's palette paint combo.

And man was it white when exposed to direct sun light. It just jumped off the canvas.
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MHMG

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Re: OBA free vs. RC resistance to UV
« Reply #28 on: August 30, 2015, 10:04:53 pm »

You only need fading and color change data of the sort already posted on the Aardenburg website.  That type of study is relatively easy to complete ...

It hasn't seemed so easy for me, but I understand what you are saying :)

best,
Mark
http://www.aardenburg-imaging.com
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Ernst Dinkla

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Re: OBA free vs. RC resistance to UV
« Reply #29 on: August 31, 2015, 04:46:46 am »

I agree with you completely.  Maybe the paper manufacturers feel that they don't need to do much innovation as there are already enough choices out there in such a fragmented market.  I also think that TiO2 being a huge commodity chemical is a lot cheaper than bariums sulfate.

It is not just the TiO2 being a commodity but the PE paper base + TiO2 + OBA construction is a commodity in itself and has been available like that for decades in the analogue period too. The chromogenic, silver halide or inkjet coating can be applied afterwards. A change in the culture of the industry is needed to make an RC paper with other whitening agents available, it is already difficult to find an RC paper base without OBAs applied.

I have used the Epson Proofing White Semi-Matte RC paper with no or little OBA content for several years now after I discovered its properties in my measurements for SpectrumViz. At that time I found only one user on the web that was not using it for offset etc. proofing purposes.

BaSO4 is a commodity too but one that has a higher price for the opaque whiteness level the paper manufacturers want in their papers, the very thin PE foil can not store much of it so would be less opaque white. The Baryta label on non RC papers does not always represent a high level of BaSO4 used either to put it mildly. Most will have other whitening agents in the mix. Some Baryta added is enough for marketing purposes.

https://www.chemours.com/Titanium_Technologies/es_US/tech_info/literature/Plastics/PL_B_Polymers_Light_Science.pdf

BaSO4 does not compete with OBAs on UV light absorption like TiO2 does. For example OBAs deeper in the paper base could still get enough UV when BaSO4 is used at the front of the paper. TiO2 is more opaque (based on fierce scattering etc) and it also absorbs UV light to emit the energy as heat beyond the visible light spectrum. So theoretically BaSO4 + OBAs could be a good combination for neutral to cool white papers (OBAs will still degrade though) however I do not know whether BaSO4 + OBAs mixes in inkjet papers behave better in time than TiO2 + OBAs do, could be even worse.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots



« Last Edit: August 31, 2015, 04:49:15 am by Ernst Dinkla »
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Ernst Dinkla

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Re: OBA free vs. RC resistance to UV
« Reply #30 on: August 31, 2015, 05:38:21 am »

One response from a representative of a popular water based coating confirmed my suspicions that the binding property of the coating (cross linking technology) that gives it strength to protect Canvas from cracking when doing a gallery wrap, will also prevent it from flowing through the micro-porous coatings.

As I read the Wiki entry on PVA, it looks like that is the same type of suspension or emulsion that I'm talking about.  See https://en.wikipedia.org/wiki/Polyvinyl_acetate and follow the link to the article on "emulsions."

I'm skeptical that the water-based materials are going to help the adhesion of the inkjet receptor coating to the base.  They are designed to and do protect the surface of the print, but they may not get at the issue we're discussing. 

Paul
www.PaulRoark.com

Paul,

I use the abbreviation PVA too loosely. I had the Poly Vinyl Alcohol in mind and not the Polivinyl Vinyl Acetate. The PolyVinylAlcohol is used throughout paper constructions as a binder and is a real dissolved polymer. Its protection grade will not be high but for binding it has the better properties.

BTW, on binding/protection, there used to be an inkjet vinyl roll material that could be printed on Encads (at that time) with dye inks. Lower in the vinyl printing side layers was a wax or resin (two types I recall) that would embed the top print layers in the wax when the material was thermally treated in an infrared curing station after printing, sheets pulled through. For outdoor signs. First it was called, tried to find some information on the web but all seems vanished.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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