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OBA Optical Brightening Agents

 
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Wittybebop
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PostPosted: Sat Oct 04, 2014 9:36 pm    Post subject: OBA Optical Brightening Agents Reply with quote

Does this just apply to the face of the stamp or is it also on the reverse/gummed side.

TIA Dave.
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cdj1122
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PostPosted: Sun Oct 05, 2014 3:38 am    Post subject: Reply with quote

The OBA, as I understand it is a coating on the paper as delivered. It is sometimes called FCP or OCP, "Fluorescent Coated Paper" or "Original Coated Paper."
That would put it on the face if it were added, but I suspect it was worked into the paper and at times migrated from front to back f the pp[er as it sat in the roll, depending on how the paper manufacturer handled the order and even how the roll was fed into the press for printing.

So I guess the answer is a firm "Yes, No and Maybe."
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tangles2010
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PostPosted: Tue Oct 07, 2014 2:59 am    Post subject: Reply with quote

I'm no expert, but I've generally found the face of the stamp is different Are you after low OBA stamps (in which case just compare them to stamps which you're certain have a higher amount of OBA and see if your low OBA stamps have a duller appearance - which should be visible on the face of the stamp)? Or are you after FBO stamps? The classic items there are the readers' digest coils I guess. In the past I've found that in my darkened room the FBO coils have a yellowish face compared to normal, but that could be down to my UV lamp and whatever other lighting was coming into my kitchen at about 11.30pm! Anyway, I wouldn't always wager that I have an infallible method for low OBA stamps but the face of the FBO stamp did appear to be pretty significantly different.
Daniel
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phos45
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PostPosted: Tue Oct 07, 2014 5:00 pm    Post subject: reverse side papers Reply with quote

when separating low-oba papers - best viewed from back side ... face colour affect intensity flour-reactions
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Wittybebop
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PostPosted: Fri Oct 10, 2014 8:42 pm    Post subject: Reply with quote

Thanks I have seen subtle differences in the front of the stamp and has lead to my somewhat confused asking of the question, I have however noticed a marked difference on the back of the stamp, as confirmed by Phos45

Thankyou.
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reintjedevos
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PostPosted: Thu Nov 13, 2014 11:53 pm    Post subject: Reply with quote

OBA's can be found in BOTH the coating AND in the paper "stuff" itself!

All combinations are possible and in all intensities! No OBA in the coating, OBA in the stuff, no OBA in the stuff but OBA in the coating.....

Sp just establish the presence of OBA's both from the front as well as from the back!!!!
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Thunderbird1
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PostPosted: Mon May 16, 2016 6:42 am    Post subject: Reply with quote

I'd like to pick up on this thread, specifically regarding FBO.

I'm rummaging thru a pile of 2.5p Rose-Madder mint singles. These are 0B and are DG 25.12.x. I believe the SG numbering is U97.. I'm particularly interested in identifying DG 25.12.2a (FBO) which comes from an RD1.4 coil. According to DG glossary, it states:

FBO:
Fluorescent Brightener Omitted, (more correctly: Optical Brightening Agent omitted). A mistake of paper manufacture. Stamps printed on this paper were issued in error and command a premium. They are creamy in appearance compared with those printed on the normal paper.

Looking at the online Connoisseur catalogue, chapter 2, page 33ff. http://connoisseurcatalogue.net/catalogue/chapter2.pdf it seems that FBO has something to do only with PCP1 printings, but not PCP2.
Interestingly enough, the Connoisseur catalogue also mentions a difference between a 'substandard phosphor coating' and an FBO which DG does not list.

Can someone help me identify an FBO single and possibly a 'substandard phosphor coating' with use of natural light, SW / LW UV or other means?

Reading Daniels post above, he says that the stamps would have a yellowish face in a darkened room, but thats not an infallible method. And phos45 views from back side, but what is he looking for - a difference in what?

TIA for any advice. Marc
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crazyh1
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PostPosted: Mon May 16, 2016 9:48 pm    Post subject: Reply with quote

Hi Marc,

the FBO is asy to spot under long wave UV. The normal stamp has a bright response with the lamp illuminated - compare to any FCP, PCP, ACP stamp to get an idea of the normal (yes I know PCP and ACP are a little different from each other, but for a quick reference this is fine). The FBO is very dull, you can't miss it when you see it. I'd provide some images for you but I'm in a hotel about to fly off on holiday.

As to whether you look at the back or front of the stamps;
With the change to FCP from OCP in the 1970s, the brightening agent was added to the paper coating, not to the paper itself. This means that normally you should be looking at the face of the stamp for variants. That said, the paper itself can, and does (or did), contain brightening agents and thus there are variations to be seen here too. You just have to take more care when using the back of the stamp to check, as the gum can also affect the UV response.

You won't generally be able to spot an OBA stamp in normal light...unless your eye are super sensitive to subtle shades of white.

If you need something as a comparison, see if you can buy an example of the 17p Green FBO. Its a common stamp and therefore inexpensive and is an excellent example of FBO.

Hope that helps
Scott
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Thunderbird1
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PostPosted: Wed May 18, 2016 4:39 am    Post subject: Reply with quote

Hi Scott,
Thanks ever so much for that - it was just what I needed. I couldn't figure out what I needed to look for, but after you mentioned the 17p stamp, I went thru all my 17p green singles (DG 170.1.1), and guess what - I had one with extremely dull appearance under longwave uv.

Looking at the 17p under shortwave uv, I get a yellow/creamy color so now I understand what DG and Daniel mean.

I would still be interested to find out what the Connoisseur catalogue means by the variation 'substandard phosphor coating' compared to the FBO definition. Anyone out there who can answer this?

Thanks again Scott, and have a great holiday.
Marc
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tangles2010
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PostPosted: Thu May 19, 2016 11:50 pm    Post subject: Reply with quote

I've been hunting the 'substandard phosphor coating' coil myself for a while. Suffice it to say I haven't got one (as far as I know), and I don't know what it would look like either! I guess at the time the catalogue listing was written the editor knew what it meant! I've hunted through magazines of the time like Stamps or Stamp Collecting but not found anything that I recognised. This is a flaw in many catalogues, I think - they list things without really explaining what it is and how you can identify whether you have it. The same could be said of the wide range of Machins that have been lumped together as 'AOP' varieties over the years.

That said, I do know a collector who claims to know someone with the 'substandard' coils. I'll try asking him again to see if I can get a description of what to look for.

Best wishes
Daniel
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Thunderbird1
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PostPosted: Sun May 22, 2016 6:45 am    Post subject: Reply with quote

Hi Daniel,
It would be great if you could get an exact identification method for the 'substandard phosphor coating'. I've also checked the MCC Catalogue and they list it too e.g. CHCD3Ab, but unfortunately I cannot find the identification method for it.

Is it safe to say, that the 'substandard phosphor coating' only applys to the Readers Digest 11p Multivalue coil, or do you think other coils could be affected?

Any news would be great
Thanks, Marc
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phos45
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PostPosted: Sun May 22, 2016 12:37 pm    Post subject: Reply with quote

flour-phosphor reactions vary greatly with any issue from bright to dull to none. visual inspection alone, does not register the intensity or absence of ink.

invest in the shixin icard camera - which allows image capture of both iriodin layer and flour-phosphor under LW uv light source. it comes with dbase ... but can be ordered without ...

http://www.shixin-china.com/1350.html

http://www.ebay.ca/itm/Stamp-Coin-Camera-Quickly-Photograph-Collections-Always-in-Focus-New-Innovation-/182117701169?hash=item2a670f9631:g:vfEAAMXQLoZR01~5[/img]
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crazyh1
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PostPosted: Mon May 23, 2016 1:14 am    Post subject: Reply with quote

Marc,

I'd be wary of drawing too large a conclusion from the MCC also listing an item. Not because the book is necessarily in error, but I have long suspected that the MCC merely replicates parts of the listings of the Connoisseur. Note that there is an acknowledgement to the Connoisseur and James Skinner in the MCC intro notes and many of the descriptions & valuations are identical. Thus the two may be referencing the same original source.

I use both books, as well as Deegam, SG Specialised, plus a myriad of dealer & auction lists to flesh out my knowledge sources. No single text covers everything and I still have a lot of material that isn't listed anywhere (I don't really collect based upon a book as such, although I used to).

I would love to have access to the original source reports of all of these varieties as its entirely possible some were wrong in the first place. In my other area of QV line engraved this type of issue exists where variants have been recorded for circa 100 years and its only recently that research is proving the erroneous nature of the original reports!

Scott
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tangles2010
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PostPosted: Mon May 23, 2016 4:08 am    Post subject: Reply with quote

Sensible words Scott. I sometimes think some of the listings are really made up to get greater sales from completists. Connoisseur lists some shades of the PiP issues which it has being printed after these stamps had already changed back to standard Machins, for example! Mind you, it was said that Gibbons invented most of the KGV shades after the War to beef up its sales, so I guess we have in a nutshell the conflict of interest that faces a shop that is also a cataloguer. Or a collector I guess - one wants to list the things one has at exorbitant prices!

So take some things with a pinch of salt until you know they really exist. My beef is often with the other extreme - things do exist but nobody knows what they look like because catalogues don't tell you. Many years ago I collected KGVI and I used to love the Commonwealth catalogue because they would illustrate plate varieties nicely. A note or two on things like 'substandard phosphor coating' surely wouldn't go amiss! Or on AOP - for example, there are three different cylinders of the 9p violet with AOP varieties and the AOP effect is different in each case, but you would hardly know that from MCC. And I don't think it helps to lump together something like a 'phosphor wash' that covers all or much of a stamp, with a stamp that has lots of additional very thin vertical bands or - at the most ridiculous extreme in MCC - the Enschede values with thin specks of phosphor which may simply be rubbing from stacking sheets together.

As I understand it the substandard coating is on the RD coil only. I'll contact my friend - one never knows! Though as he has been promising to get me an example for the past three years, he might duck for cover!

Daniel
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crazyh1
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PostPosted: Mon May 23, 2016 5:15 am    Post subject: Reply with quote

well said Daniel.

Not knocking the completist collector, most of us started out in that groove I suspect, but the catalogues (especially SG) are not the be all an end all. They provide a particular view and not always one that is consistent across the whole catalogue. Your 9p AOP example is a case in point. In recent years I have deliberately sought out pieces which show the progression of such varieties; eg. progressive missing phosphors, phosphor washes, imperfs, etc. By doing this it has helped me to understand the true nature of the variety and what the books are trying to describe. What it also does is demonstrate quite starkly how the majority of the books are something of a mixed bag.

Ultimately the collector has to make a choice on the form of their collection, and that's absolutely right and proper, but there is a risk of the retailer come cataloguer's conflict of interest getting in the way. In the QV 1d reds there is a controversial example. There is a listed shade of 'Plum', they get certs to this day as they carry huge SG catalogue values as compared to the few pounds of the 'normal'. The Plum shade did not carry a premium value until the late 1960s (or there abouts from memory), when SG abruptly started to escalate the value of that shade, its now several hundred pounds! The real contentious element is that there is good chemistry which will demonstrate that this is not how the stamp looked when it was issued, rather it is a changeling as a result of the dirty air of the late 19th century onwards........but to pull it from the catalogue would put a lot of people out of pocket.

Take that thought and swing back to Machins - 6p FCP/PVA missing phosphor....... SG used to list it, now removed with a note to say that it was found to show some slight UV reaction. Deegam still lists it. I have a cylinder block which shows a very faint afterglow, but not in the sense of phosphor bands, more a general afterglow. SG would say it fails as they presumably demand zero afterglow. Deegam might say its right. Others, who knows. There are other missing phosphors where there is always a slight afterglow, so shouldn't these be pulled from the SG catalogue too?!

My view ultimately is that we should all gain as much experience as possible by looking at a high volume of material. Even if you don't have the funds to buy the stuff, pop to local auctions and have a rummage, hold them and look at them....there's no obligation to buy. This way you get a better understanding and can more easily see through some of the vagaries of the friendly catalogue editors out there.

Always a contentious debate this one.

Scott
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Gooner
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PostPosted: Sat May 28, 2016 10:56 pm    Post subject: Reply with quote

Just a quick note that is slightly off the main point of the topic.

I think we should acknowledge that the only catalogue/handbook that is entirely neutral as it has no real interest in the VALUE of a variety is that published by Deegam.

All the rest mentioned are associated in selling stamps that they put a value on.
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cdj1122
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PostPosted: Sun May 29, 2016 12:22 am    Post subject: Reply with quote

" ... the only catalogue/handbook that is entirely neutral as it has no real interest in the VALUE of a variety is that published by Deegam. ...

An excellent point, Dave, especially in light of the financial difficulties Gibbons has fallen into recently.
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crazyh1
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PostPosted: Sun May 29, 2016 2:10 am    Post subject: Reply with quote

Quite right Dave, although as much as I prefer Deegam as my main reference, it does have its gaps.

Also a valid point Charlie - I have been monitoring SG's financial situation for a while and it does demonstrate what many of us believed had been the case for several (or many) years....that SG was being run by money men and had lost sight of the normal collector. Assuming they survive their situation, and the odds are better now than in their troubles in March, there will have to be a correction in their attitude. Whether that is in any way reflected through the catalogues time alone will tell.

Scott
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