Need Help Identifying These 2 Paper Types

Hi Stamp community

I was cleaning the gum off these 2 used Washington 5c stamps and I was wondering if anyone could help me with identifying the 2 paper types in the image.
The one obsorbs water really unevenly, I have seen this on some GB stamps from the early 1900s as well, which I am not sure why and the other has these parallel lines on it which almost looks like ribbed paper but I did not know the 5c washington was printed on a ribbed paper?




any help will be really appreciated.

Could you please give us a scan of the front? Sometimes we can glean some information from that side also.

Since the 1908-21 Washington's were not printed on ribbed paper that leaves other possible answers. One is that the stamp was stored in one of those old-time photo albums with ribs of sticky stuff on the pages. Another is the stamp has picked up the characteristics of the cover paper it was removed from. I am sure that others will have ideas, but these are mine. If the stamp were from the 1922 series breaker bars might be considered but I am assuming since these are 5 cent Washington's that can be ruled out.

That was my thought also, but the OP also said
which leads me to believe that they just recently soaked off the gum, and are now looking what is underneath. But, I also agree that the ribbed look is just a manifestation of storage or what it was actually attached to.

Good morning

Thank you so very much for the advice, I really appreciate it. I am really still very new to this hobby and trying my best to learn as much as I can because I really enjoy the hobby especially trying to figure things like this out.

So both of these stamps were hinged in the same album since my grandfather or great grandfather put them in here, I cannot say exactly but for a very long time, the same as all the other stamps from other countries and none of the others look like this except a few from Poland which I believe Poland does have ribbed paper stamps.The hinge even took a very small tiny chunk off the middle of this stamp with it which upset me a bit so the envelope was removed a long time ago.

Can anyone give me some advice as to why the stamp on the left looks the way it does? I would really like to know why some stamps absorb the water so evenly, the whole stamp becomes translucent but some don't....

@Partime as requested attached is a scan of both from the front, both stamps are swapped around in this scan. Thank you for the assistance.

Hi all, I know this is an old post, can anyone explain why these are a different color under back light. I know the Pan American is wood pulp hence the yellow-brown glow, why is the other one a much cooler color?

Gum on the Pan-Am?

Hi Rogdcam, both stamps have gum removed. So it is nothing to do with the composition of the paper?

In the below picture the Locomotive is a know Rag paper stamp, the Pan American a known Wood pulp paper stamp, so what is the 5c Washington Franklin ?

This seems like basic paper science to me...this is what Chat GPT says about the matter

Have any of you actually read the book titled "The Washington Franklins, 1908-1921 -- Martin A Armstrong" ?

There is still gum residue on the stamp. You can see the white of the paper on the edges and in places in the body of the stamp. This is a simple topic that you are making into a science project. Where are you going with this might I ask?

Hi Rogdcam, not sure what you are going on about exactly, yes obvioulsy would be near impossible to remove every molecule of gum from between the paper fibres without causing the stamp damage however the white you are seeing are just sections where the light is passing through easier, gum would actually make it harder for light to pass through the paper.

To answer your questions I was hoping to get an expert opinion, one that is unbiased and knows about paper and can tell me what kind of paper this is