Fluorescence Or Not To Be.that Is The Question

Question about fluorescence on BK49 and BK49b Booklets.
341a, NF / Death
341ai, FL
341aii, HB
341aiii (as 341a but Stitched pane) BK49b only
341aiv, MF

Is it possible to have fluorescence other than NF / Death on 341aiii (stitched) BK49b? Under UV light mine appears to be LF and MF, if it exists which Scott number should be assigned to these panes?

I attached a photo and never realized how difficult it was to have the right lighting and adjustment to take a decent shot with a UV lamp. This is the best I could do and it is far from perfect but we can still see a difference in flourescence between the two pane. Head to tail it's only to see a bigger white background side by side, it gave a better comparison.

Let me know if I am wrong on this .....

From what I see is the pane on the left maybe has a more violet tint.

Wert & angore, under normal light, the paper is not showing any violet or bluish tint but I realize that the paper is slightly whiter on one of the two pane it's minimal but noticeable under naked eyes on front and back through out the dextrose gum.

If there has been some kind of alteration to whiter the pane this as not affected the blue color of the stamps in any way.

Is this slight whiter difference sufficient to give a false fluorescence reading?

I wont stand on this for long, it give me headheach....

Have you tried long wave UV light? It is possible that the paper has been chemically treated and that would show under LWUV but much less under short wave UV ( Hibrite paper ).


Peter

Yes, I also checked under LW and the floorescence does not appear at all, at best it is dead fluo on both.

I am gona try to buy a desktop type UV short and long wave lamp (254nm for fluorescence & 366nm for tagging) instead of the flashlight type that I am using now. It work ok but the bluish lights comming from those leds create fussy and uneaven reflections.

SAFETY INFO: A wavelength between 300 and 400 nm can penetrate the cornea and be absorbed by the iris or the pupil. High energy short wave blue light between 415 and 455 nm is the most harmful. Direct penetration of crystals into the retina causes irreversible photochemical retinal damage. SHORT WAVE greater thant 300 nm are bad for eyes.....

I do not like the longwave LED lights as the illumination is poor. I prefer the tube.

Under LW UV have you looked at these with a 10x loupe? The difference could be due to luminescent fibers found in a number of Canadian stamps. The concentrations of fiber will lead to varying degrees of fluorescence such as LF, MF and HF. Note HF is not the same as a true hi-brite. Paper on many Canadian I have looked at would be NF or dead if not for the luminescent fibers. The luminescent fibers are added to brighten the paper.

Hi Pollux,

I have worked with the Wilding series for quite a while and I can tell you that there are many levels of fluorescence within each broad category (Dead, NF, Low, Medium High, and Hibrite). I am not sure if you are familiar with the Centennial series, but in Douglas Irwin and Murray Freedman's "Canada: The 1967-73 Definitive Issue" Second Edition, they broke down the intensity of the fluorescence into a scale that ran from 0 to 12 (0 being Dead and 12 being Hibrite). In addition, they also broke the issue down by the ultraviolet colour that was reflected back. For the 1-Cent Brown, for instance, they had 18 different colours that they classified.

The fact is, there was no specific recipe for paper manufacturers, and each batch of paper could be very different. You can specialize in fluorescent papers as deeply as you want, or completely ignore it. You have to sort of set your own bar. For many, it becomes a frustration.

Case in point, I am currently working on a lot of of 200 1-cent Karsh Plate Blocks. So far, I have identified 13 different colours of paper, all of which are still considered to be on Dull Fluorescent Paper. Fibres, or "flecks" as they are often called, were not used until 1959/1060, which was past the printing period of the Karsh Definitives.

A word on lamps. The best one I have ever had, and still use, is a Spectroline Brand (my model ENF260C). To my mind, the battery operated lights are only good for taking away with you. You need a plug in verion at home. I see there is a similar model now on ebay https://www.ebay.ca/itm/274922922900?etmp=no

I have a metal break, so I made my own stand for it, so I can work for hours under the pleasant glow of a Longwave light.

Thanks Brad905, your information is greatly appreciated, I take note of it. You are right, it is frustrating to try to catalog fluorescence knowing that the slightest difference in the basic composition can give several mismatches even if it shouldn't be.
The Wilding, Cameo and Centennial series for me are very interesting to collect, a lot of variants but a pleasant challenge.
I'll take a look at the lamp you mention.

Have a nice day.

Pollux.