Double Paper Study Regarding Banknotes

Wanted to share the steps I've found to be the most useful when searching for double paper.

This is nothing definitive but only my opinion.
I believe that if these steps are met, *you can be confident in a double paper submission without having to separate the papers* and risk damaging the stamp.

I've gone through quite a few 3c'ers to finally be able to recognize certain features, and I'll include them below.

This 30c was the latest. I didn't want to risk opening it because I was already confident in what it is, but for the sake of validation and showing it on here I found a potentially good perf and separated it (picture 5).
You can use a knife's edge to flick it up and down a few times and it may pop open. Graze it like you would opposite of sharpening the knife on a piece of flint.
(if you know a better way please let me know!!)

It's good to note that the compression used to join both pieces together was not near as strong as the compression used in the creation of either particular side of the stamp. Both sides are quite stiff, despite what the picture tells you, and so much so that a 'pop' occurs on separation rather than a tearing from a single compressed piece.


Here are some key attributes to look for without separating it:

1) Ping test checks out for hard paper, despite seemingly having the 'girth' of soft paper.

2) The paper is stiff, but the texture is not completely flat / solid in nature compared to that of hard paper.
Under magnification, the stamp is extremely fiberous on both sides, and resembles a thin sheet of compressed sawdust board like those found on construction sites.

3) Under light, the color is a deep brass, and much more saturated than a typical soft paper. All the doubles I've examined share the same color.

A mesh presence is somewhat noticable, but not as consistent as that seen on soft paper.
There MAY be enough meshy presence to fool you into believing it is soft paper, but that alone doesn't invalidate the possibility of a double paper or intermediate hard peper type.

4) While inspecting the perforated edges under magnification, there will be some areas that have 'dimples'. This is where both sides didn't evenly detach when the stamp was separated from the plate block.
I feel like this is the most obvious step, as it would certainly be difficult to find any double paper where not even the slightest trace of misalignment in both sides could be found under magnification.

I don't know if this has been touched on in depth before, but hope it helps some people when researching this variety.

Nice to revisit that old thread...there's a post in there from Bill Robinson, who was my favorite dealer and, sadly, is no longer with us.

Thanks Roger, should have included that one at the very top.
The reason for this very post is because of the OP's original question which was quickly lost in the weeds.
Very informative otherwise. Reads like a book.

True, never did get any kind of answer, your opening post is the closest I've heard to an answer, Thanks, Stephan.

Welcome! And thank you Phil for the kind words, and also for starting the thread that motivated me to start this one. It was a great question to ask.

Only problem is the 30c stamp is very unlikely to be double paper.

Sinclair 2010 wrote:




Ditto to that, Winston!

Stephan, your discussion of this topic will lead uncritical readers to the senseless destruction of numerous soft paper stamps, and probably to a few actual double paper stamps as well. Let me ask if you have read the patent specifications Steel wrote for his original patent application in 1869. If so, then you know what to expect from the two sides of the stamp under strong magnification.

In response to your question in this thread I will here write what I originally wrote in the thread to which you referred (and for which a link was provided by rogdcam )




As for stamps still mounted on cover, I would suggest you not even consider attempting that until you are very familiar with the distinctiveness of the upper layer of double paper. I have certified examples of double paper on cover, and the PF did not need to remove the stamps to determine that. But I do not recommend trying to ID double paper on cover until you really know what you are doing.

essayk, The PF needs the customer to be as clear as possible on their submission and payment.

Here is a summation of what you expressed:
"1) It has to appear hard
2) It has to behave differently
3) It has to be noticeably different
4) It has to show cleavage under 30x magnification."

I'm sure you are a very competent grader but if you are not willing to give clear, descriptive examples of what to look for, it is irresponsible to tell people that they have no choice but to spend money on a submission.
Double Paper is very unique, and not that difficult to describe.
People should only be making submissions they're 90% confident in, because that's how the system is currently set up.

I am simply helping with that, and stand very confident in everything posted above.

After reading essayk's comment, I'll add these 2 points:

1) You NEED to be able to discern the difference between hard and soft paper before attempting to understand double paper.
There should be absolutely no confusion on whether you're holding a soft paper or hard paper before questioning a candidate for double paper.
This is something worthy to practice in general, and can be fun to quiz each other on amongst friends in the hobby.

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2) Soft paper can make tears as well, but...
*There is a big difference between a soft paper tear, and a double paper separation*.

-A soft paper tear will be soft and flimsy. It will naturally curl one way or the other, and will blow wherever the wind takes it.

-A piece of double paper when separated will be extremely stiff, and will have no problem standing perfectly erect in whichever direction you pull it towards.
Think hair gel scene from 'There's Something About Mary'.