It is currently Tue Jun 28, 2022 12:09 am (UTC [ DST ])

Post new topic Reply to topic  [ 2 posts ] 
  Print view Previous topic | Next topic 
Author Message
 Post subject: Wilding violet phosphor differences ?
PostPosted: Thu Jul 30, 2020 12:32 pm 
User avatar

Joined: Sun May 03, 2020 11:19 am
Posts: 159
During the last couple of years in my exploration with regards to the multiple crown Wilding papers, I came across a type of violet phosphor variation that does not seem to have been mentioned in any of the catalogues as with some of the papers that I have also discovered.

It concerns the reflectiveness of the phosphor bands when held at an angle to the light, I would find that some of the bands appear to be of a Matt finish, whereby others have a Glossy finish and seem hardly discernible at all, indicating that a different type of phosphor was used (similar to household paints such as Matt and Gloss finishes). Another collector reported to me that with many of the violet phosphors the afterglow can vary quite considerably from ½ second to around 3 seconds, this may not be associated to my findings but may be related.

Initially, I thought that the difference was only focused on individual values but on further inspection, I found that this was not the case, as stamps of the same denomination was also discovered to have similar variances.

The method of application of the bands are usually stated in the catalogue photo,typo etc. but no mention has been made with regards to these findings that are quite clearly noticeable when inspected.

Here is a view of one of my findings, I am sure that you will notice the band differences between the 10d and 1/- values in the attached scan.
Could it be the same phosphor but applied differently ?
(369.77 KiB)

This is followed by stamps of the same denomination that are also similarly affected, in this case the 5d value.
(255.83 KiB)

It's quite possible that you may also have some of these variances in your own stamp collection, check them out as there are several values to be found with this type of anomaly !

Here's another one, it's the 6d that can be added to the list as these bands are not identical !
(399.32 KiB)

Here is a combination of 3 variances discovered on the 2d value, the first scan showing the difference between the Matt and Gloss type bands under normal desk top light.
(457.77 KiB)

But on this second scan (using the same stamps) taken under long wave ultraviolet light, the ink used to print the stamps appears to be a completely different shade, as with the paper used, with the larger block being a more chocolate brown on cream paper as against the smaller block giving a bluish hue on whiter paper.
(714.72 KiB)

Therefore, 3 variations in total has been discovered on this particular value being :-
1) A difference in the paper (cream and whiter).
2) A difference in the ink used to print the stamps (as seen under UV)
3) A difference in the phosphor bands later applied (Matt & Gloss).

I await any comments you may have to offer on the subject.
Thank you, WM.

Last edited by Wilding Mad on Tue Jan 04, 2022 8:18 pm, edited 1 time in total.

 Post subject: Re: Wilding phosphor variations ?
PostPosted: Mon Dec 20, 2021 12:08 am 
User avatar

Joined: Sun May 03, 2020 11:19 am
Posts: 159
I put this differential phosphor bands finding (including scans) to the late professor Austin J Barnes back on the 27th & 30th of July 2020 and this was his reply firstly on the 27th >

"Similar to the previous phosphors, violet phosphor was applied contained in a resin (cyanuric acid-formaldehyde) and thus had there been any change in the phosphor this would not have affected the appearance of the bands. The effect that you are seeing could be due to variation in the resin or more likely the solvent (toluene or xylene) and other additives used to make up the phosphor ink for printing. Incidentally were these latest images under natural light or long wave uv? (not that that affects the above)
Best wishes

This next reply was on the 30th July 2020. >

"As I previously told you my work on the Wildings was mainly around 50 years ago so you keep testing my memory (I disposed of my collection in 1973). At that time we did look at these types of reflection but with a view to differentiating flexography from photogravure – the latter glazes the stamp image from the pressure of the plate whereas the former (with rubber stereos) does not. I don’t recall any comment specifically on the appearance of the phosphor bands.
You have commented on the analogy with matt and glossy paints which seems possibly fruitful. My knowledge of this area is limited to choosing which to use in decorating my house! However it seems likely that the appearance of the finished product will be affected by the solvent mixture used and additives such as drying agents. Just possibly the printers were experimenting to achieve faster drying for the newer high speed printing presses".

Based on the above mentioned replies by professor Barnes, it would appear that there is still a lot to be discovered with these multiple crown Wildling stamps especially with the phosphor band variances and cream papers printed since 1964, which may have been overlooked in the past, at one point I thought that Austin had denied the existence of the later cream papers but he then rectified his understanding giving this reply >

"You misunderstand my “denial” that cream papers exist on later issues – my objection is that the context in which you use the description implies that they are the same as the earlier cream paper printings. At some stage in our voluminous correspondence I wondered whether the later cream papers arose from the use of oxidant(s) to remove OBAs – which would be very interesting if it were the case. Certainly I feel strongly that whatever terminology is used it needs to make clear that the origin of the latter cream paper printings is different from that of the earlier ones".

Upon which I explained to him that the later oxidised cream papers was of a more translucent nature in order to differentiate.

Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

Who is online

Users browsing this forum: No registered users and 2 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group