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Author Topic: Why OBAs in this paper?  (Read 6913 times)

rasworth

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Re: Why OBAs in this paper?
« Reply #20 on: March 11, 2018, 05:36:44 pm »

I guess that's where we disagree - I don't consider the results from stimulating the paper with a uv free source any less real than stimulating with uv included.  Both results are valid if they reflect real viewing conditions, and if those viewing conditions can be practically selected.  I practiced for several years only using a normal i1Pro, and often had problems profiling OBA papers.  I've been much more successful using the i1Pro uv cut for those papers.  And for those of use still doing hand scanning it is significantly more work to scan with both instruments in order to compare profile results.

You measured Epson Prem Luster M0 b*=-6.72 and M2 b*=2.5.  I measured RR UltraPro Luster M0 b*=-8.0 and M2 b*=-.6.  I believe both M2 results are just as true as the M0 results, and equally useful.  I agree that without the M0 measurements we wouldn't know anything about the OBA content, but that doesn't make the M2 measurements incomplete, they are sufficient to create a profile for use where the viewing conditions match, i.e. no uv.

Richard Southworth

Added by edit - I was answering Andrew, didn't realize other posts had occurred.  BTW both of my instruments are i1Pro 1s, second generation.
« Last Edit: March 11, 2018, 05:40:34 pm by rasworth »
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Doug Gray

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Re: Why OBAs in this paper?
« Reply #21 on: March 11, 2018, 05:37:02 pm »

Whoops - this is getting a bit difficult, as double-negatives can be - maybe just at my age. Does your iSis work like the i1Pro2 using a dual scan mode to create the M2 condition? More generally how do you create the M2 data file? With M0 you get the kind of bluish reading we expect from Epson PLPP. Turning to the M2 reading, you say you don't trust it because "it isn't measuring without a UV cut filter." What does this mean - that it is measuring with a UV cut filter? Or measuring with a light source that doesn't excite the FBA? If so, I would expect something like the 2.5 because that M2 measurement is supposed to be neutralizing the OBA impact by not seeing or suppressing the UV - somehow. It's the "somehow" that I would emphasize here - seems that the 2.5 is an approximation, because the filtering may not be accurate. But give or take a bit, we should still expect an M2 b*reading considerably warmer than -6.7 if it's counteraction of the UV is "in the ballpark" - right? If so, the M2 reading may be closer to eventual paper white (after OBA fading) than is the M0 reading, but we don't know how close. Am I making sense here?

I believe all iSis scanners scan using M2 (uV cut) because they use a "white" led. Then they do a second scan, if selected, using uV only which they read and add in various amounts to generate spectra and Lab values for M0 and M1.  The I1Pro 2 uses an incandescent lamp which reads M0. The second pass, if selected, activates a uV light only and reads the fluorescent response. It then calculates M2 and M1 from those.
« Last Edit: March 11, 2018, 05:43:26 pm by Doug Gray »
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digitaldog

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Re: Why OBAs in this paper?
« Reply #22 on: March 11, 2018, 05:38:21 pm »

Yes Mark the Isis measured the row twice.
And observing OBAs is as simple as viewing it under a black light from the cool 1960s or a newer LED black light which are available for little money (you don’t have to own a spectrometer)
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Ernst Dinkla

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Re: Why OBAs in this paper?
« Reply #23 on: March 12, 2018, 07:40:24 am »

I guess that's where we disagree - I don't consider the results from stimulating the paper with a uv free source any less real than stimulating with uv included.  Both results are valid if they reflect real viewing conditions, and if those viewing conditions can be practically selected.  I practiced for several years only using a normal i1Pro, and often had problems profiling OBA papers.  I've been much more successful using the i1Pro uv cut for those papers.  And for those of use still doing hand scanning it is significantly more work to scan with both instruments in order to compare profile results.

You measured Epson Prem Luster M0 b*=-6.72 and M2 b*=2.5.  I measured RR UltraPro Luster M0 b*=-8.0 and M2 b*=-.6.  I believe both M2 results are just as true as the M0 results, and equally useful.  I agree that without the M0 measurements we wouldn't know anything about the OBA content, but that doesn't make the M2 measurements incomplete, they are sufficient to create a profile for use where the viewing conditions match, i.e. no uv.

Richard Southworth

Added by edit - I was answering Andrew, didn't realize other posts had occurred.  BTW both of my instruments are i1Pro 1s, second generation.

The safest way to get a print profiled for more display conditions is selecting an OBA free paper and measure it with an UV enabled spectrometer then create the printer profile.
The second safest way is selecting an OBA free paper and measure it with an UV cut spectrometer. After that come the worst combinations. Starting with an OBA loaded paper like the one you have is asking for issues at some point. 99% of RC inkjet papers have OBA content, very few so little that it is no issue. The shift of the paper white in time can be caused by UV light, light, gasses like oxygen, ozone, dark storage after exposure. Framed behind plain glass the fluorescence effect already is reduced, behind UV blocking glass it is absent. Yet that does not mean the OBAs are totally free of degrading there. Display conditions vary and UV light may be part of it or not, either caused by daylight entering or not so good converted by fluorescents in the CFLs. In short it suffers more of changing conditions than paper without OBA does.

Since the introduction of OBAs in papers after WWII consumers are more and more used to a bluer white point where UV fluorescence adds brightness to the normal whiteness of papers. Paper manufacturers introduced the Brightness property where the blue part of the spectral range is used to measure the "light reflection", they promoted that Brightness property. Most RC paper bases used to apply inkjet coatings on are already containing OBA, the coating may contain them too. For an RC inkjet paper manufacturer it is harder to create a neutral paper without OBA that gives similar Lab L light reflection that papers with OBA can achieve by this physics trick.  So when consumers like to get that OBA look and it is easier to make, you get the paper you have.

The spectral plot of a Red River paper close to your paper is attached together with some alternatives with lower OBA content. Your's is most likely a Mitsubishi manufactured type. The PIctorico one too but with less OBA and Red River has a similar one. The purple plot is one of the RC exceptions with almost no OBA, Epson Proofing White Semi-Matte. Little OBA in the paper base, plenty of other "normal" whitening agents aboard to flatten the spectrum reflected and no OBA in the inkjet coating. You probably will not like its texture and it looks warm despite being neutral in the CIE definition. The dot lines show the OBA as measured at the back of the paper (black underneath) so more or less the paper bases with OBA content they started with.

UV-cut spectrometer raw readings are massaged one way or another when printer profiles are created with them. The white point is not the white point when OBAs are activated nor is it the white point of the paper base as if no OBA was added at all, the created white point is a virtual one representing a generic neutral paper. As shown the brightness created by fluorescence can differ a lot between OBA containing papers yet near neutral white points are usual for the printer profiles created that way. From the left to 575nm an OBA effect could exist but goes unnoticed by spectrometers with UV cut lamps + UV cut sensors, depending on how flat the remaining reflected spectrum is a profile can be made but what is actually raw measured for some must be way warmer than neutral, red end high and steadily descending towards the blue side. In that sense the Lab a figure is more revealing when white point numbers are taken from profiles made that way, green/yellow reflection of that paper being low and measurable, you would expect a positive Lab a number there but it is slightly negative in your profile. Green plot lines representing your paper.

Although it starts from UV enabled measurements and aims at the estimation of the OBA effect, extrapolations included, this article is interesting to read. The attitude to declare UV cut measurements as dealing with the OBA paper content in practice is a false one, kind of ostrich head in the sand approach. Also notice that the estimation mentioned there improves when the non OBA reflection is already quite neutral, read "normal" whitening agents already created a flat spectrum without the OBA effect. Then the so called D50 measurement versus so called D50 viewing conditions and actual light sources used for both.
https://www.argyllcms.com/doc/FWA.html


Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
March 2017 update, 750+ inkjet media white spectral plots
« Last Edit: March 12, 2018, 07:45:15 am by Ernst Dinkla »
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rasworth

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Re: Why OBAs in this paper?
« Reply #24 on: March 12, 2018, 10:27:15 am »

Ernst,

Thank you for your reply.  I have one minor disagreement - the paper with similar characteristics to RR UltraPro Luster (subject of my post) is RR UltraPro Satin, represented by the brick red line on your graph.  The green line represents Arctic Polar Luster, which I also own and have profiled, and it is indeed a "hotter" paper with higher OBA content.  Red River recommends using their UltraPro Satin profile with the UltraPro Luster paper.

So per your statement "The attitude to declare UV cut measurements as dealing with the OBA paper content in practice is a false one, kind of ostrich head in the sand approach", what would you recommend as an alternative?  I own two instruments, both i1Pros, one normal and one uv cut.  I've had more visually pleasing results building profiles for OBA papers using the uv cut instrument.  In the old days using a normal instrument with Profilemaker, even though they claimed to sense and correct, I was always fighting a tendency for the resulting print to tend toward yellowish.  I don't have that issue with the uv cut instrument.

Richard Southworth
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digitaldog

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Re: Why OBAs in this paper?
« Reply #25 on: March 12, 2018, 10:50:10 am »

I guess that's where we disagree - I don't consider the results from stimulating the paper with a uv free source any less real than stimulating with uv included.
Look at the numbers man! Look at the name (UV CUT).
Quote
Both results are valid if they reflect real viewing conditions, and if those viewing conditions can be practically selected.
There's no viewing conditions yet. Just numbers from the Spectrophotometer. And I said, and I'll repeat: there are no rules! If you can you should measure both ways and build two profiles do so. Then make prints and test. Enough said.
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Ernst Dinkla

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Re: Why OBAs in this paper?
« Reply #26 on: March 12, 2018, 11:58:18 am »

Ernst,

Thank you for your reply.  I have one minor disagreement - the paper with similar characteristics to RR UltraPro Luster (subject of my post) is RR UltraPro Satin, represented by the brick red line on your graph.  The green line represents Arctic Polar Luster, which I also own and have profiled, and it is indeed a "hotter" paper with higher OBA content.  Red River recommends using their UltraPro Satin profile with the UltraPro Luster paper.

So per your statement "The attitude to declare UV cut measurements as dealing with the OBA paper content in practice is a false one, kind of ostrich head in the sand approach", what would you recommend as an alternative?  I own two instruments, both i1Pros, one normal and one uv cut.  I've had more visually pleasing results building profiles for OBA papers using the uv cut instrument.  In the old days using a normal instrument with Profilemaker, even though they claimed to sense and correct, I was always fighting a tendency for the resulting print to tend toward yellowish.  I don't have that issue with the uv cut instrument.

Richard Southworth

Richard, if your UV-enabled spectrometer, i1Pro Normal as you call it, is worth its money and it reads Lab 95.6 0.9 -8.0 then that paper has more relation with the RR Artic Pro Luster that my UV-enabled i1Pro measures as Lab 95.8 1.4 -9.8. The RR Palo Duro and UltraPro Satin have respectively a Lab b -3.4 and -3.1 here. All the RR RC papers I measured fall in these two classes.  That has been measured some time ago though. Checking all the 300 grams RC versions that I have and anything near b -8.0 gives me this screengrab, does not change my opinion on what is happening with the numbers. RR may purchase from Felix Schoeller or have the same supplier Moab uses. Something is odd if RR says the OBA content is low,  UltrPro Satin class,  and you measure Lab b -8.0

BTW that  -.5   instead of  -0.5  use is highly confusing for me, could be my glasses or my EU metric background.

Use a low OBA content RC paper, measure it with both spectrometers. Make two profiles, greys neutral, compare. Make another two profiles with the greys adapted to the paper white, compare the four. Not familiar with i1Profiler but settings like that should be aboard. Then check the white point numbers again.


Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
March 2017 update, 750+ inkjet media white spectral plots


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rasworth

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Re: Why OBAs in this paper?
« Reply #27 on: March 12, 2018, 12:50:11 pm »

Red River doesn't claim low OBA for UltraPro Luster, just that it matches UltraPro Satin.  The confusion may lie in the fact that the current version of UltraPro Satin is 4, considerably "whiter" than the older versions, which may be what you measured.  A RR support person told me that their Palo Duro Satin is more or less equivalent to the older versions of UltraPro Satin, considerably warmer than today's version.

And I'll try to keep the 0 in front, i.e. -0.x.

Richard Southworth
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rasworth

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Re: Why OBAs in this paper?
« Reply #28 on: March 12, 2018, 01:34:11 pm »

Ran a non-quantitative test with the black light, RR Arctic Polar Luster on the left, and the subject of my post, RR UltraPro Luster 300, on the right.  You can draw your own conclusion as to relative OBA content.  I don't have any UltraPro Satin for comparison.

Richard Southworth
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MHMG

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Re: Why OBAs in this paper?
« Reply #29 on: March 12, 2018, 01:45:07 pm »

Aardenburg Imaging & Archives reports a "UV fluorescence" figure in each test report and in the database list as well. We use the following criteria to determine if the paper has no OBA, low OBA, moderate OBA, or High OBA content.

No OBA:  absolute value of M0-M2 readings measured b* difference <0.3
Low OBA: absolute value of M0-M2 measured b* difference = 0.3 to 2.5
Medium OBA: absolute value of M0-M2 measured b* difference  = 2.5 to 5.0
High OBA: absolute value of M0-M2 measured b* difference ≥5.0

As a general rule of thumb, papers with no or low OBAs test better in Aardenburg light fade tests, i.e not contributing much in the way of highlight color changes which contribute adversely to the overall Aardenburg Conservation Display rating for a given printer/ink/media combination.

Medium OBA content starts to impact the score and undermine the inherent goodness of any reasonably light fast ink set performance.

High OBA content inevitably and significantly undermines the inherent light fade resistance of any decent dye-based or pigment based ink set.

Lastly, the "yellowing" which accrues due to OBA burnout is not just about the loss of fluorescence causing the paper to revert to its underlying "natural" UV filtered media whitepoint. It's also about the fact that the degradation bi-product(s) of the OBA burnout don't necessarily remain colorless over time. The faded OBAs typically produce an additional metastable (i.e., light- bleachable but not stable) yellowing/discoloration component when retired to dark storage (or when displayed under low to moderate illumination levels). This additional staining can double or triple the amount of discoloration observed by the viewer merely due to loss of fluorescence. I've seen degraded whitepoint values of high-OBA content papers climb above b*=20.0 for media stored in the dark after 100 Mlux hour accumulated light exposure for an additional year or more and then remeasured.

Moral of the story: Media with high OBA content like many of today's RC photo media are well matched to traditional dye-based photos where the fading of the dyes typically occurs faster than the degradation of the RC photo paper. However, with modern synthetic dye or pigmented inkjet systems, today's RC photo inkjet papers aren't stable enough in their own right to achieve what the latest OEM inkjet inks deserve in terms of a stable paper to maintain their higher levels of light fade resistance over time.

cheers,
Mark
http://www.aardenburg-imaging.com
« Last Edit: March 12, 2018, 01:56:02 pm by MHMG »
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rasworth

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Re: Why OBAs in this paper?
« Reply #30 on: March 12, 2018, 02:17:35 pm »

Mark A.,

Thank you for your contribution to this thread.  I noted in your test results for the Epson 3880 you had data for Epson Ultra Premium Glossy, which has an OBA high rating.  Have you seen yellowing as you described for this paper?  Have you detected any awareness/concern about this issue by paper manufacturers, i.e. are they developing any new less susceptible OBA compounds?

Richard Southworth
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rasworth

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Re: Why OBAs in this paper?
« Reply #31 on: March 12, 2018, 03:48:20 pm »

Ernst,

Decided to "cheat" on my homework assignment, and just do spot measurements with Measure Tool (see attached image).

First I measured Moab Juniper Baryta, claimed to be OBA free, with both of my i1Pro instruments:
  Normal   l*a*b* = 97.2, -0.6, 2.5
  uv cut    l*a*b* = 97.2, -0.4, 2.8
I consider this to be a reasonable match between the two instruments.

Now the OBA laced Red River UltraPro Luster 300:
  Normal   l*a*b* = 96.3, 1.0, -7.6
  uv cut    l*a*b* = 95.6, -0.7, -1.0
No surprises I believe.

Interestingly to me, test prints from my 3880 on these two papers, viewed in my normal environment which I believe is uv minimal, appear very similar.  The main difference is the slightly creamier white of the Moab.  I'd say it was a toss-up, except of course for the over 2 to 1 cost difference.  Profiles were constructed per my usual approach, uv cut for OBA paper and normal for the OBA-free paper.

One last question - do the OBA compounds degrade as fast in a low uv environment, both emissivity and yellowing?

Richard Southworth
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MHMG

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Re: Why OBAs in this paper?
« Reply #32 on: March 12, 2018, 04:39:46 pm »

Mark A.,

Thank you for your contribution to this thread.  I noted in your test results for the Epson 3880 you had data for Epson Ultra Premium Glossy, which has an OBA high rating.  Have you seen yellowing as you described for this paper?  Have you detected any awareness/concern about this issue by paper manufacturers, i.e. are they developing any new less susceptible OBA compounds?

Richard Southworth

I'm working on an Aardenburg light fade database II which will integrate both light fade and dark storage combined results. It's definitely a work in progress, but once the dark storage yellowing issues are integrated into the overall test result, the current Epson Ultra Premium luster and glossy papers are going to rank among the worst RC inkjet photo papers on the market. Canon RC photo papers (Luster and Semigloss pro, but not Platinum) will have about half of the light-induced post exposure staining as the Epson papers.

Are the manufacturers working on improvement? Hell no! The customer can't see the problem when looking at initial image quality, so the customers aren't complaining...yet! But once the yellowing problems begin to be talked about in forums like LULA's printers and printing forum, I'm optimistic that media longevity improvements will be made. Epson's Proofing Paper White Semimatte is a good example of a low OBA resin coated (RC)  paper exhibiting far less yellowing/discoloration over time. That said, EPPWSM does not have a typical "photo" surface texture that will appeal to all RC photo paper enthusiasts, but it would be easy enough for Epson to specify an "Epson Premium Luster Natural" RC photo paper with all of the good longevity characteristics of Epson Proofing Paper White Semimatte. The printmaking community just has to insist that the manufacturers do better!

cheers,
Mark
http://www.aardenburg-imaging.com
« Last Edit: March 12, 2018, 04:45:57 pm by MHMG »
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MHMG

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Re: Why OBAs in this paper?
« Reply #33 on: March 12, 2018, 05:03:00 pm »


One last question - do the OBA compounds degrade as fast in a low uv environment, both emissivity and yellowing?

Richard Southworth

Not as fast, but fast enough. Blue wavelength radiation has enough energy to fade OBAs, dyes, and pigments as well... the UV wavelengths from direct sunlight striking a print on the wall typically contributing to 2-3x increased fade rate, but again, UV excluded light still has plenty of energy to fade artwork hanging on the wall. Many framers say UV filtered glazing stops fading. That's wrong. The truth is that it typically slows the process 2-3X, which is, of course, significant, but lowering the light level on display 2-3x is also incredibly trivial. So, in the long run, print collectors should worry far more about light intensity on display (it can routinely vary 10-100x or more) than on the choice of glazing which frames their prints on display.

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

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Re: Why OBAs in this paper?
« Reply #34 on: March 12, 2018, 05:17:15 pm »

The printmaking community just has to insist that the manufacturers do better!

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

And/or just focus one's purchases on papers that meet one's taste in respect of OBA content. For example, Epson Legacy Platinum has no OBA (they and my spectro indicate) and it does have the the kind of luster/gloss surface good for providing wide gamut, High DMax results using PK ink. Ilford Gold Fibre Silk has much less OBA than Epson PLPP (according to my spectro) so it should do much better than PLPP in your combined testing. Hahn Photo Rag Baryta is similar to Legacy Platinum. So there are options on the market now to meet quite a variety of tastes in the matter.

Now, when these discussions of OBA arise, I like to take a peak through "history" to see what I find. You may remember that back in the day when Epson first made archival inkjet printing on the desktop possible with the P2000 printer, the choice of papers was very limited compared with what we now have. In those days, (year 2000) I printed on PLPP and Enhanced matte - EMP (both Epson). I still have those prints, so 18 years of inkjet history. I just now made some measurements of paper white (b*)  and here's what I got:

PLPP from year 2000;
M0: -2.3
M1: -2.9
M2: -0.11

PLPP from an early 2017 package:

M0: -3.9
M1: -4.8
M2: -0.7

This would seem to suggest that (a), yes the OBA presence is considerable in this paper (as we always knew) and (b) either the recipe changed or the OBA in the old stock has faded, given the less negative numbers in that series compared with the recent ones. There is no appearance of yellowing, and the paper white looks uniform, but if this is a trajectory and it carries on for another couple of decades, one may well be telling a different story - one about paper white starting to look yellowish.

I also measured the 18 year old EMP, and here's what I got:

M0: -0.8
M1: -2.7
M2: +5.7

We also know this paper was/is choc-a-bloc OBA loaded. Unfortunately I don't have any current stock as a comparator. But the old stuff again, still looks OK, there is no visual appearance of uneven OBA fading; however that M2 result is a bit worrisome - very warm, perhaps indicating that this paper will eventually look rather yellowish.

My visual references are under Solux 4700.
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MHMG

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Re: Why OBAs in this paper?
« Reply #35 on: March 12, 2018, 05:39:08 pm »


Now, when these discussions of OBA arise, I like to take a peak through "history" to see what I find...

Your history sounds a lot like dark storage in enclosures/document storage boxes and/or cabinets for the last couple of decades where both light exposure and Ozone exposure are very low. In that context OBAs hold up quite well. It's display environments and subsequent storage environments after time on display where the trouble arises.

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

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Re: Why OBAs in this paper?
« Reply #36 on: March 12, 2018, 05:51:58 pm »

Your history sounds a lot like dark storage in enclosures/document storage boxes and/or cabinets for the last couple of decades where both light exposure and Ozone exposure are very low. In that context OBAs hold up quite well. It's display environments and subsequent storage environments after time on display where the trouble arises.

kind regards,
Mark
http://www.aardenburg-imaging.com

Ah sorry - good catch - I forgot to mention that. You are correct. The prints are bound into books that remain shut (and for this set, slip-cased) on a shelf. So very little exposure. But even so there is evidence here of OBA fading, wouldn't you say?

The other thing that's very noticeable is how far inkjet printing has advanced since then - the improvements have been on the whole gradual from one version to the next, but add them all up and it's just a sea-change in vibrancy, black points, gamut, whatever.
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Doug Gray

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Re: Why OBAs in this paper?
« Reply #37 on: March 12, 2018, 05:58:11 pm »

I also measured the 18 year old EMP, and here's what I got:

M0: -0.8
M1: -2.7
M2: +5.7

We also know this paper was/is choc-a-bloc OBA loaded. Unfortunately I don't have any current stock as a comparator. But the old stuff again, still looks OK, there is no visual appearance of uneven OBA fading; however that M2 result is a bit worrisome - very warm, perhaps indicating that this paper will eventually look rather yellowish.

My visual references are under Solux 4700.

Interesting. I once left a printed sheet of EMP I had done some test printing on next to a book after I was finished with it. Some years later I dug out the book, noticed the paper edge that was not covered by the book had significantly yellowed. I didn't measure it but would guess b* had increased well over 5. I haven't seen significant shifts for paper kept in their boxes. Mark A's comment that uV yellows 2-3 faster than regular light sounds right.
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MHMG

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Re: Why OBAs in this paper?
« Reply #38 on: March 12, 2018, 06:17:37 pm »

...The other thing that's very noticeable is how far inkjet printing has advanced since then - the improvements have been on the whole gradual from one version to the next, but add them all up and it's just a sea-change in vibrancy, black points, gamut, whatever.

And yet, inkjet prints are still highly fragile when compared to other traditional photographic processes in numerous ways, i.e., abrasion resistance, gas fade resistance, humidity resistance for dye-based systems, sensitivity to VOCs, even light fade resistance with poor inks or media, etc. There's much room for improvement, so why should we give manufacturers of inkjet printers, inks, and/or media a free pass nowadays? Better to keep up the customer pressure for improvement alive and well, IMHO.
« Last Edit: March 12, 2018, 06:23:13 pm by MHMG »
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MHMG

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Re: Why OBAs in this paper?
« Reply #39 on: March 12, 2018, 06:30:07 pm »

... But even so there is evidence here of OBA fading, wouldn't you say?

Yes, most likely ozone attack coming in from the edges of a photo album type of storage condition. OBAs are extremely sensitive to ozone when located in microporous ink receptor coatings. OBA impregnated papers can fade in OBA fluorescence, especially around the paper edges, in just a matter of days due to ozone incursion.
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