RCMP Centenary 612. Maybe Untagged?

I am new to all this but I was going through the box of stamps still in glassine envelopes from my grandfather's Canadian collection (now mine) and came across three blocks of four celebrating the RCMP Centenary from 1973. This is just around the time my grandfather died and these are probably some of the last stamps that he acquired.
In cataloging them, I decided, on a lark, to see if I could see the tagging on the stamps. I can clearly see it on the 10c and 15c stamps (#s 613,614) but I am unable to see the tagging on these four 8c. I realize that tag identifying can be difficult and I am just using my daughter's "Top Secret UV Pen" light to see the tags. But maybe, just maybe I have something here. Any advice? Comments? Thoughts?

Having fun with old Bill's stamps in Toronto!
-Doug

Hi Doug,
Always fun to sift through an old collection. This stamp comes from a period where the tagging on some Canadian stamps is known to fade or migrate to other stamps. This is NOT one of the issues that has this problem. Normally this stamp should have exactly the same tagging as the other two RCMP stamps even using a "Secret UV Pen".

A variety of this stamp without tagging is listed as 612T1 in the latest Unitrade specialised catalogue and a single mint NH-VF copy lists for $100 instead of the normal $0.30. So it looks like you might have a very nice block there.

That would indeed be nice. But should you not check this with something a bit more scientific than your daughter's Top Secret UV Pen? I have sold these pens through Scholastic Book Fairs, and they really do not give off enough energy to check luminescence on a stamp.

Peter

Currently circling the purchase button on the Canada Post website for their table top UV light. I should get it, if not just for science! ;-p

For an inexpensive step up from "The secret UV pen", search ebay for:

Mini Aluminum UV ULTRA VIOLET 9 LED FLASHLIGHT BLACKLIGHT Torch Light Lamp

I recently got one for less than C$1.50 and it easily shows tagging on Canadian stamps.

I ended up ordering a 6 in 1 light, UV magnifying glass and microscope. This one, in fact. https://www.canadapost.ca/shop/sale...ecution=e1s1 We shall see if it's any good. I figured I could use a magnifying lens or two as well. So why not, eh?

Staples sells a very good UV lamp that is used to check currency. Been using it for years. Cheap.

Update:
The new lens/light showed up yesterday and I finally got a chance to see if there was tagging or not. Turns out these are tagged. Just not as plainly visible as the other two in the series.
Fun while the dream lasted... Who am I kidding? It's still fun! I guess I've got the bug!

I use that same 6 in 1 magnifier and it is very handy and inexpensive. Good buy ! It also has a built-in microscope that is small but works fine!

The UV light on that magnifier is good for spotting flaws on older stamps as well as checking the tagging on newer stamps.

I quite like the 6 in 1, having used it for a couple of weeks now. My only complaint is having to cycle through all of the light settings to get to the one you want or to just turn it off. Not a big problem but the constant clicking noise I'm making must be getting on my wife's nerves! :-)