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PostPosted: Fri Sep 04, 2020 9:22 pm 
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During a session of soaking off some Harrison Machins, I noticed after using tissue paper as a source for drying them that the tissue had become impregnated with a fluorescent substance, and could only presume that the fluorescence had come from the surface that the stamps and been initially coated with, concluding that this fluorescent substance was highly fugitive once moistened and could easily contaminate the stamps in soak.
This is the tissue in question and my observation under UV as to it's condition after use, here is an attachment attributed to that fact .....,

After seeing the tissue, I then decided to examine some of the stamps, again under longwave ultraviolet light and discovered that they had also been affected by their coating once submerged in water, as can be seen in the next attachment.
(186.66 KiB)

Is there a way to prevent this from happening other than by sweating them off individually ?
Another important question is "Was the substance used toxic" ? WM.

Last edited by Wilding Mad on Thu Oct 07, 2021 4:05 pm, edited 3 times in total.

PostPosted: Thu Sep 10, 2020 10:02 am 

Joined: Fri Nov 02, 2012 7:00 pm
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Location: East Anglia

QV surface-printed stamps have very fugitive ink, but it never occurred to me that there might be a problem with the coating of early decimal Machins, not just to the stamp being soaked but its companions in the soak.

Would floating them face up on the surface of the water, letting the water seep through from below, with individual rinsing, reduce the problem to acceptable levels?

As to toxicity, I would not have thought there was any, even though H&S was not so important almost 50 years ago. Or if there was, not enough to harm humans. But best perhaps not to let your dog/cat/fish drink/swim in the residual water.

PostPosted: Thu Sep 10, 2020 11:05 am 
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Regarding toxicity: while I don't have data on this specifically (other than a general recollection that toxicity was one reason for not using inorganic phosphors), I did come across a c.1970 report in the PO archives analysing the gum on some registered envelope flaps that contained a trace of arsenic.

The conclusion there was that it wasn't remotely enough to cause a problem even if someone licked lots of them, but it was certainly enough of a concern that they were testing the gum. So I expect that any substances used as phosphors were tested for toxicity beforehand.

PostPosted: Thu Sep 10, 2020 11:12 am 
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Good morning Winston,
Your method of soaking off in order to prevent contamination occurring sounds helpful and I could also add that the stamp be removed from it's paper ASAP once removable and placed in a clean bowl of water to prevent further contamination prior to drying them.

I suppose that by now millions of these stamps from this particular era will have already been processed (soaked off) and their owners are unaware of their condition, especially if they don't possess a longwave 'black light' to check them out.

It would be interesting to hear from other collectors with similar findings to add to this particular topic.

Thank you also Moz regarding possible toxicity of gum.

Perhaps due to some of the factors mentioned the self adhesive was introduced on October the 19th 1993 and fluorescent surfaced papers were no longer produced from 1992 onwards due to changes in technology and possibly environmental aspects as an improvement.

But even then with their new technology, the Royal mail still have to rely on the local postman to cancel some of their mail !

What a farce, WM.

Last edited by Wilding Mad on Mon Oct 04, 2021 8:48 am, edited 1 time in total.

PostPosted: Thu Sep 16, 2021 9:45 am 
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Soaking the 17p Dark Blue Machin centre band off paper.
The use of the long wave ultraviolet lamp has many advantages in detecting fluorescence in papers, but whilst soaking some stamps off paper I noticed a very peculiar reaction in that when the stamps were wet and laid out to dry on a tissue paper, a definite difference was noticed between two different types of paper that they had been printed on, and with a little experimentation in combination with a long wave UV light I soaked off some 17p dark blue Machins with centre band and compared the differences found in combination with the use of long wave ultraviolet light, note that both types of paper had equal soaking time. Therefore I was quite amazed with the outcome as the damp translucent type stamps showed a high degree of fluorescence whereby the damp more opaque looking ones gave a very weak reaction giving rise to the fact that two different papers had been used to print these stamps, this reminded me of the cream and white versions of the earlier multiple crown Wilding definitives listed in the SG part 3 specialised catalogue.

Below you will find three examples of these particular 17p stamps as seen under different exposures of light.

Item 1. As seen under artificial light (fluorescent lamp).

Item 2. The same stamps but using a light combination.

Item 3. The same stamps but under long wave UV only.

This experiment is only recommended for used stamps, but it does show you the vast difference found using the damp paper method, try it for yourself on this and other values and see what you can discover !

Note: Once the stamp paper had dried no difference was noticeable in the visible spectrum between the two variations discovered, but the difference could still be observed using long wave UV.

The magic is in the water !!!!!

Here is another issue concerning the 1990 17p Christmas stamp with similar characteristics using the damp paper method and L/W UV, it can be seen that the damp translucent paper is fluorescent whereby the damp opaque paper is non-reactive under L/W UV. >


If all of the different coatings have been listed such as OCP, FCP, PPP, PCP l & 2, ACP, etc.
Then shouldn't the different types of base paper being used also be included irrespective of the coating ?
After all, the definition of "variety" is that of a recognisable difference that has occured, both of which can be seen clearly within the two papers exhibited in the above attachment, as seen under long wave ultraviolet light.

Another value I discovered being on different papers whilst using the damp paper method was the 15p "Harrison" centre band stamps, after soaking them off paper I placed 3 of each of the two types of paper discovered (opaque and translucent) on a separate piece of tissue whilst they were still damp and took images of them, one under fluorescent light the other under L/W ultraviolet, as you can see there was a major difference in their response to ultraviolet, the reaction is not because of a coating but of the actual base paper itself, that was produced and used in the printing of these stamps.
<see images >


Once again whilst soaking off some 15p stamps a problem which I thought had previously been rectified with the additional use of optical brightening agents or oxidation seems to have appeared once again in the form of a contaminated paper that contains fluorescent fibres, this contaminated paper has been used to print the 1990 15p 150th anniversary of the first adhesive postage stamps, I am sure that when you have seen them personally you will be in agreement that they are reminiscent of some of the multiple crown Wilding stamp papers exhibited in another posting I recently made. >

Note the similarity.........

Unlike the contaminated papers of the Wilding series, these Machin stamps have a fluorescent coating on the printed side which tends to hide the fluorescent fibres, therefore the contaminants can only be observed from the reverse on stamps with FCP.

Last edited by Wilding Mad on Tue Nov 30, 2021 3:14 pm, edited 3 times in total.

PostPosted: Thu Sep 30, 2021 10:29 pm 
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Using the damp paper method once more I decided to take a look at the 1990/1992 NVI 1st class Orange stamps, the majority of which I have to hand are mainly individuals from booklets with either imperf top or imperf bottom, but I did find a few from sheets with perforations all round, and on inspection I discovered by using the damp paper method in combination with an ultraviolet light that three specific papers could be identified.
A} a non-fluorescent paper (opaque when damp) produced for booklets.
B} a medium fluorescent paper (translucent whilst damp) produced for booklets.
C} a highly fluorescent paper (opaque when damp) produced for booklets.
D} a highly fluorescent paper (opaque when damp) used in sheet printings.
Papers C&D appear to be identical just different perforations.
<See attachments>


Papers A and B used for photogravure printings whereas papers C and D was used for stamps printed by lithography (Walsall and Questa).

The 22p flame red stamp.
On using the damp paper method to distinguish differences in types of paper used, I noticed that the 22p flame red stamp had been produced using two different base papers, one being of a translucent nature whilst damp reacting fluorescent under long wave UV and a non reactive paper that appeared opaque when damp, these differences can be seen in the following two attachments >


Another factor to be noted is that during my damp stamp paper experiments I found the opaque papers to be less porous than the translucent ones, and consequently the opaque papers had a greater buoyancy, the two types of paper virtually separated themselves in the water, one sank (translucent) being more absorbent, whilst the other had a greater tendency to float once removed off their envelope clippings and placed into a separate clean water container.

Another one for your scrapbook is the 20p turquoise stamp also known as a sea green shade that first appeared in public on the 23rd of August 1988 printed on a coated paper classified as ACP (advanced coated paper), the trouble is someone has forgot to mention that two basic papers that was coated have been used to print this stamp, and with the use of the damp paper procedure I was able to discriminate between the two varieties that exist, one being on a paper that is opaque when damp and not fluorescent and another that is translucent when damp but fluorescent under longwave UV.
<See the two attachments>


There are possibly many more values with variations of paper yet to be discovered using this method.

Perhaps Scott Kibby the new decimal Machin consultant may be able to add a few comments or additional information as to my findings relating to the damp paper method and CONTAMINATED papers discovered, or could it be he is unaware of the differences that I have found !

Here are a couple of 22p stamps both with different base papers, issued within a month of each other in 1991, the dinosaur stamp being printed on a non-fluorescent base paper whilst the roses stamp was printed on a highly fluorescent one, both stamps having conventional FCP >

But that is not the complete picture, I can now report on finding two distinct papers used to print the 22p Dinosaur stamps, the variations was discovered whilst using the damp paper experimentation procedure, the like of which can be seen in the following two attachments.
Please note that all stamps depicted in the following two attachments were damp at the time the shots were taken.

Attachment 1: as seen under normal fluorescent lighting.

Attachment 2: as seen under long wave ultraviolet.

No doubt many more issues have yet to be found that have been affected in a similar way as it would appear that more than one base paper has been used to print British decimal stamps during this period irrespective of the various types of coatings that have been used.

Curly wurly, spring or pigs-tail stamp papers
Over the years due to changes in postal technology the need for different types of paper has been sought and experimented with in which to accomplish various tasks and requirements needed, one type of paper springs to mind (excuse the pun), as this particular one has a tendency to curl up like a spring once submerged in water and can be awkward for the collector after soaking off paper, especially during the drying procedure. The worst offending examples being around 1980/3 period and to a lesser degree 1984 stamp papers, in fact stamps as late as 1992 (Queens Accession) have been recorded on this type of curly type paper when damp.
Here are a couple of examples >

Why this type of paper was ever introduced originally is open to speculation and conjecture, thankfully it was eventually replaced, but was this type of paper ever officially recorded on its induction or as to when it was replaced as was the Wilding papers in 1962 ?
Have records been kept ?
I've also noticed that some of the definitives issued during the same period in question such as the 14p grey-blue and the 22p deep blue gave a similar reaction when immersed in water.

It's surprising what you can discover with a little drop of H²O and a bit of ingenuity, the above findings are just a little something to whet your appetite, see what you can discover using this damp paper method I devised in order to discriminate the different variety of papers used !
But watch out for those fugitive coatings in doing so !!!!
Have a nice day everyone, Wildling Mad.

Last edited by Wilding Mad on Mon Dec 27, 2021 12:03 pm, edited 1 time in total.

PostPosted: Sun Nov 07, 2021 12:57 am 
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Perhaps Einstein was correct when he gave this quotation, as seen on this 38p stamp of Gibraltar issued in 1998 >


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