Bluish Paper Under UV Light? Please Help...

I have read in another thread about it being possible to tell that a stamp was printed on bluish paper (paper which was made with 35 percent rag stock instead of using 100% wood pulp) by examining it under UV light.

I am aware of different colr backgrounds making the "grayish" appearance stand out.

But just exactly what do you see under UV light that stands out on a bluish paper stamp?

Thanks


-IBFS

IBFS, can you identify the other thread?

Peter

I only ask about the UV test because the bluish gray tint can be easily faked with the use of dye. I believe a UV light test, if it exists, would be the best way to tell the difference.

Kevin- This is old, but it is the one I was referring to...

https://goscf.com/t/6958


-IBFS

IBFS, Thank you for the thread. I have no answer for you, but I have trouble with a similar problem.
I too keep reading to distinguish different paper types under UV light, but don't seem to get anywhere.

Peter

Sorry I called you Kevin, Peter.


-IBFS

I was trying to figure out who the Kevin was you were addressing! I figured it was me, and there was no harm done!

Peter

Out of curiosity, I put a 367 & 369 side by side and looked at them under both short & long UV. I could discern no differences. Placing them on an orange background did make the paper color difference quite a bit more obvious.

Placing them on orange or yellow paper is the best way to make the gray color "pop" out so it is more readily identifiable. However, faked/dyed stamps will ALSO "pop" on these papers, so the best way is to simply break down and buy a cheap pre-certified copy of the real thing and use it for your reference copy. A 2c with faults can probably be had for around $50. But having it as your reference will be invaluable in the future and if it helps you correctly ID ONE stamp, it will pay for itself.

This question may sound silly, but how do you know if the "copy of the real thing" hasn't been dyed, if it hasn't been certified? Or maybe I don't understand...


-IBFS

I believe he is using the term "pre-certified" to mean "already certified", not "not yet certified".

I believe he is using the term "pre-certified" to mean "already certified", not "not yet certified"

That is what I took Bill's statement to mean.

I hope Bill will chime back in, but I believe with pre-certified he means already certified. After all, pre-cencelled means already cancelled?

Peter

His use of the word "copy" is what is throwing you off. He means that you should buy an example of the actual stamp that has a certificate already, but may have some defect that keeps its value down. Such a stamp is the best kind of reference you can have, since you can compare untested stamps against an example of the real thing.

Whew.... sorry for the confusion! As essayk (and others correctly explain) I mean a stamp ALREADY certified as a genuine bluish paper........

Papers that have been dyed blue often show evidence of the alteration (for instance, darker/deeper blue on the perf tips & edges, where exposed paper fibers absorb more ink.) I've never seen an especially deceptive "dyed" bluish paper fake...

Genuine bluish papers almost always have more than their share of carbon inclusions too. If you think you have a bluish paper and you're not seeing at least a couple small, embedded, ugly black dots, there's a reasonably good chance it isn't...

I had a dealer at a stamp show attempt to sell me a dyed 2-cent W/F as a genuine bluish. Its fairly obvious when you have one in hand. I don't mean to imply he knew it was dyed.