Need Help With Modern Stamp Backing Paper Counterfeit V. Genuine

Hello everyone! 1st day on the site so please be kind. 45 year collector is pulling the rest of his hair out due to confusion on backing paper of moderns. I picked up Powwow and Spongebob stamps from either the Methuen, MA or Salem, NH PO months ago when they came out and I just tested the backing paper. It glows under LWUV where I've read it's supposed to be dead. I frequent the USCA website which has a great counterfeit reference area. I have the imperf stamp sheets and they are dead. Is it possible that the USPS is using two different papers? One for full sheets and one for sheets that will cut into panes? I can't believe that the PO is selling counterfeits. Someone please let me know what you think. Can you please check what you have and get back to me? Thank you!

I don't know these specific issues but from experience with modern self-adhesive booklets, there can be a range of reactions when shining long wave (365nm) light onto the backing, for the same issue.
So it would not surprise me that on regular stamp sheets, one can detect the same behaviour.

I checked the ones I have and both issues have a large quantity of bright luminescent fibers mixed in which glow brightly under LW UV. They are added as optical brighteners which is one way to make paper look brighter. if you have a 10x magnifier, look closely and you can see these fibers. As mentioned above you can see can also see quite a bit of difference in the luminescent properties of the backing paper. Same is true for the front/image side.

https://goscf.com/t/90299

Scroll down on this post and you can see some examples of backing paper variation. While some are from different plate numbers for that stamp, as I mentioned you can see this with stamps with a single plate number.

I just checked them under UV 254nm and UV 380nm for you:



UV 254nm



UV 380nm



Hope this helps!

Sochummy, where did you get your fake? I have attached a picture of my imperf over the perfed pane from the post office. On the website: https://www.usca.nl/wp-content/uplo...Nov-2025.pdf
it shows that the fake position is on the upper left like you have. If you notice my pane, it is lower right making me think it's genuine. I have others from the post office that do the same thing like my army, navy and marines which is the second picture. I bought these from my post office as well. And only the Navy is supposed to be real? Can't be.
I'm hoping someone out there has one that they bought at a post office to prove mine are genuine. I can't believe a guy at the post office is switching them.

My two cents is that the USPS and BCA aren't concerned with backing paper since the only security that matters is the actual financial instrument, the stamp. The spec for the stamp paper is phosphor, block tag but who cares about the disposable backing paper. The backing paper isn't going to be scanned by any machine; it is going in the trash if the stamps are actually used for mailing.

sabfan1217, the fake ones are abundant on ebay. The real one was taken from a sealed USPS package that was ordered directly from the USPS website. I recommend buying stamps on the USPS website, as they come sealed, so you know for sure they are genuine.

What is your goal? Do you only want to know if your panes are genuine, or do you also want to study the fluorescence of the backing paper?

If your goal is the former, there are several details you can examine on the stamps, including the fluorescence of the stamps under short UV light, rather than relying on the backing papers.

The goal is to weed out any counterfeits and when I saw the website mentioning dead vs. glowing backing paper, it raised a flag. I've been checking the stamps first with shortwave to detect tagging but the problem is the counterfeiters are now tagging their stamps so I thought the backing paper would be the tell tale sign. I guess I'm looking for proof that someone bought one direct from a local post office that glows. I just checked my Boston stamp show panes and they glow and I know these are genuine so that makes me feel a little better knowing that BCA might be using different papers. All the descriptions (exaggerating) on USPS say "Phosphor, Block tag". It's no wonder many stop collecting moderns but you can't if you're a completist like myself.

"The counterfeiters are now tagging their stamps"

The counterfeit tagging is almost always much brighter than the genuine tagging. Additionally, the genuine stamps' tagging has a texture of tiny dots if examined closely, while the fake tagging appears "flat".

The paper fluorescence of the backing paper can very quite a bit on modern issues so that is not always a way to tell real from fakes.

I finished going through my 2025's and they do vary alot. One had my regular pane from the post office not glowing and the imperf pane that comes from Philatelic Center glowing and you know that has to be genuine, so to me that's definite proof that you can't call a counterfeit from the backing paper glow. Thanks everyone for responding!