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Author Topic: Choosing the right paper  (Read 2260 times)

Mark D Segal

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Re: Choosing the right paper
« Reply #20 on: April 03, 2018, 10:53:22 AM »

That means pretty much all RC media and some "traditional fiber" and so-called "Baryta" papers (they may have some baryta in them but also lots of TiO2 or other whitening agents) suffer from this post-exposure dark storage discoloration, and its not pretty.


This statement struck me as well, as I too was under the impression that generally Baryta is being used either instead of fluorescing agents or with a comparatively small component thereof (comparing say with Epson Premium Luster or Exhibition Fiber). An immediate example that comes to mind is the comparison of Ilford Gold Fibre Silk with Ilford Gold Fibre Gloss. Both are Baryta-containing papers, the former with a low OBA presence and the latter with none, to judge from my readings of paper white with an i1Pro2. Epson Legacy Baryta has a  low OBA presence while Legacy Platinum has none. So the questions are whether the specific non-Baryta whitening agents in these papers that have them are TiO2 or something else, whether they are in the substrate or in the coating, and whether we have test results for these papers giving comparative indication of OBA fading behaviour and its effects.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....."

MHMG

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Re: Choosing the right paper
« Reply #21 on: April 03, 2018, 11:08:54 AM »

Mark, thank you for the further clarification. We all learn from you.
Two questions:
1. I thought only "cheap" OBAs produced a color cast when they faded.
2. I did not know TiO2 was still used in Baryta paper. I thought one of the reasons for using Baryta was so you didn't have to use TiO2. TiO2 can really accelerate fading and even damage the paper base if its sealed in a frame due to its creation of ozone when hit by UV, which is why I assumed a paper whitened by Baryta was better than one whitened by TiO2. Maybe I'm wrong.

There may well be different quality grades of OBAs with respect to lightfastness, but pretty much everything I've tested in photographic and inkjet media fades, and when in media where TiO2 is present, develops additional staining as I mentioned in my earlier post.  For OBAs used in modern photo media, the rate of fading apparently has more to do with concentration and location in the media, not necessary due to "higher or lower grade" when the manufacturer chooses to incorporate OBA.

As for Baryta papers, it's important to note that true "full baryta" inkjet media do exist, but there are some glossy/luster "traditional fiber" media where the manufacturer gets away with calling it a baryta paper simply because a little Baryta is added into the whitening layer(s) in order to make the baryta claim. A bit disingenuous, IMHO, but if one likes the look and feel of the paper and it prints well, then I suppose it doesn't matter, unless of course the media yellows significantly over time.

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

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Re: Choosing the right paper
« Reply #22 on: April 03, 2018, 11:37:37 AM »


As for Baryta papers, it's important to note that true "full baryta" inkjet media do exist, but there are some glossy/luster "traditional fiber" media where the manufacturer gets away with calling it a baryta paper simply because a little Baryta is added into the whitening layer(s) in order to make the baryta claim. A bit disingenuous, IMHO, but if one likes the look and feel of the paper and it prints well, then I suppose it doesn't matter, unless of course the media yellows significantly over time.

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

Well, this begs the question, so let me ask you specifically - do you know whether Ilford Gold Fibre Silk and Epson Legacy Baryta contain TiO2, and if so, have you been able to test them for determining whether degradation creates uneven yellowing over a given number of equivalent years of say dark storage?
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Mark D Segal (formerly MarkDS)
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mearussi

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Re: Choosing the right paper
« Reply #23 on: April 03, 2018, 12:46:24 PM »

Yes, it would be really nice to know which papers contain TiO2.

I first became aware of the problem it caused when Ctein first discovered that the ozone TiO2 created was destroying so many of his fine art framed B&W prints (mentioned in his book "Post Exposure"). Due to the lack of air circulation in framed prints the ozone builds up oxidizing both the RC paper (causing it to crack) and silver (turning it black) in only a few months. Now I don't use RC paper nor is there any silver in my prints, but still ozone can't be good for either the inkjet paper or ink. So I would like to avoid the same fate happening to any of my photos that are also framed. 
« Last Edit: April 03, 2018, 12:50:36 PM by mearussi »
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MHMG

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Re: Choosing the right paper
« Reply #24 on: April 03, 2018, 12:58:19 PM »

Well, this begs the question, so let me ask you specifically - do you know whether Ilford Gold Fibre Silk and Epson Legacy Baryta contain TiO2, and if so, have you been able to test them for determining whether degradation creates uneven yellowing over a given number of equivalent years of say dark storage?

I evaluated the original IGFS and the newer Canson Baryta Photographic amongst other papers a couple of years ago when better funding enabled access to a portable XRF (X-ray Fluoresence) unit at a local conservation lab. I had picked these two media among others for XRF analyses because they are media "look-alikes" (as is Epson's Legacy Baryta), because both papers contain low amounts of OBA, and because they were some of the first non RC media in the Aardenburg database to exhibit this light-induced low intensity exposure problem (.e.g, the post exposure yellowing I have encountered on virtually all RC media). XRF detected TiO2 in both media, and the finding supports my hypothesis that it's the combination of OBA and TiO2 which leads to this post exposure yellowing/discoloration issue.

I'm also trying to research what light intensity level on display suppresses the yellowing by light bleaching. I haven't got a firm number yet, and it may ultimately be somewhat media dependent, but it appears that lux levels below 500 lux on display are low enough that the rate of staining proceeds faster than the rate of light bleaching. So, dark storage is simply the boundary condition for not enough light to suppress the extra yellowing (above and beyond the loss of OBA fluorescence) caused by OBA-TiO2 interactions for prints on long term display.

For more info, check out the notes, whitepoint stability measurements, and the I* curves in the PDF report for ID #223 in the Aardenburg Database. HP Z3200 inks on Canson Baryta Photographique. There are several other samples in the database that documented this problem during testing for those instances where I didn't get to measure the samples soon enough after removing them from the light fade units, and thus the staining and subsequent bleaching effects can be observed in the data. As I mentioned earlier, I'm trying to implement a more formal testing protocol that will routinely check for this problem and correctly factor it into the final test scores. Screening studies to check media whitepoint stability before conducting a full test is also a good approach.


kind regards,
Mark
http://www.aardenburg-imaging.com
« Last Edit: April 03, 2018, 02:25:55 PM by MHMG »
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Mark D Segal

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Re: Choosing the right paper
« Reply #25 on: April 03, 2018, 01:01:38 PM »

Thanks Mark, that's helpful. Good to know. I hope you can keep up the good work!
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Mark D Segal (formerly MarkDS)
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Alan Goldhammer

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Re: Choosing the right paper
« Reply #26 on: April 03, 2018, 02:09:28 PM »

Mark, thank you for the further clarification. We all learn from you.
Two questions:
1. I thought only "cheap" OBAs produced a color cast when they faded.
Epson Exhibition Fiber has lots of high quality OBAs and they create a color cast when they fade

Quote
2. I did not know TiO2 was still used in Baryta paper. I thought one of the reasons for using Baryta was so you didn't have to use TiO2. TiO2 can really accelerate fading and even damage the paper base if its sealed in a frame due to its creation of ozone when hit by UV, which is why I assumed a paper whitened by Baryta was better than one whitened by TiO2. Maybe I'm wrong.
Ozone production takes place at the surface of TiO2 only in the presence of nitrogen oxides.  It's not clear to me from a chemical perspective whether this reaction can take place on coated paper as the nitrogen oxides would have to penetrate the coating.  When I studied this issue several years ago it looked like Barium Sulfate was cheaper than TiO2 and that might have been the principal reason for using it as a paper whitener (there may have been other reasons as well).
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mearussi

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Re: Choosing the right paper
« Reply #27 on: April 03, 2018, 03:30:35 PM »

Epson Exhibition Fiber has lots of high quality OBAs and they create a color cast when they fade
Ozone production takes place at the surface of TiO2 only in the presence of nitrogen oxides.  It's not clear to me from a chemical perspective whether this reaction can take place on coated paper as the nitrogen oxides would have to penetrate the coating.  When I studied this issue several years ago it looked like Barium Sulfate was cheaper than TiO2 and that might have been the principal reason for using it as a paper whitener (there may have been other reasons as well).
So you're saying that the color cast isn't just from the return of the paper back to the normal yellow cast it had before OBAs were added? So what color(s) do the OBAs create when they decay?
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MHMG

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Re: Choosing the right paper
« Reply #28 on: April 03, 2018, 04:51:36 PM »

So you're saying that the color cast isn't just from the return of the paper back to the normal yellow cast it had before OBAs were added? So what color(s) do the OBAs create when they decay?

Check out the PDF report for ID #210 in the Aardenburg light fade database. It tells what discerning printmakers need to know about Epson Exhibition Fiber paper.  The report notes plus the media whitepoint stability graph on page 5 plus the visual appearance of the target images accurately reproduced in the report which show higher and higher exposure doses turning the media more and more yellow all document the sad story of this paper not living up to its "bright white" expectations over time. Some of the yellowing is caused by loss of OBA fluorescence, but the yellowing goes beyond what can be explained solely by loss of OBA fluorescence, and this strong yellowing IS NOT caused by the OBA-TiO2 dark storage staining issue either (Epson EFP is loaded with OBA but not any TiO2, again confirmed with XRF analysis).

regards,
Mark
http://www.aardenburg-imaging.com
« Last Edit: April 03, 2018, 04:57:42 PM by MHMG »
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enduser

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Re: Choosing the right paper
« Reply #29 on: April 03, 2018, 09:08:00 PM »

From the discussion so far I'm beginning to see where caution applies in choosing paper.  As someone on this thread said, it's complicated. I almost feel like asking Mark MHMG what papers he uses for his own work, thereby simplifying the selection process.
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mearussi

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Re: Choosing the right paper
« Reply #30 on: April 03, 2018, 10:03:51 PM »

Remember that longevity is only one aspect of choosing a paper. It also has to look good with your image.

First find a paper that maximizes your image then focus on how you can make it last as long as possible. For instance, I have recently switched from Canson's Platine (no OBAs) to Canson's new Baryta Prestige, even though it has a small amount of OBAs added, because of its superior color reproduction and clarity for my printer/ink combination compared to Platine. But I also know how to protect it and slow down its fading by applying Print Shield, a spray overcoat, which, according to Mark's tests, will add approximately 25% of display life to it. I could even extend that further if I decided to use a UV glass when framing. 
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