Help Understanding Gum Errors

I was looking to see if anyone has experiance identifying an error. I have a block of 16 6c stamps from Philippine Islands of the US scott#292 and it looks like gum on the front? Any input.

In the past, stamps were sometimes inadvertently printed on the gum side, much more unlikely to have gum applied to the fronts of the finished stamps.

The previous owner may have stored them improperly.

This is an example of a stamp printed in error on the gummed side:



and this is the normal stamp:



They look quite different. And this block was gummed both sides, over the printed front side:



This is what the normal stamps look like:

Looking at the block of 16 I submitted, It looks like the sheet was being feed in the direction of the arrow then they relized it was the wrong side? Under my scope the gum looks consistant with the back and it clearly shows the perforating was done after the gum was applied. I't not consistant to improper storage, otherwith there would be gum on the perforation fibers?

Also, the gum margins in the selvage line up perfectly on the front with the gum on the back of the stamp. If this truley is a gum error, how offten does it happen? Can someone explane the procces of gumming, printing and perforating?

I would also like to know if maybe the ink was applied on top of the gum or the otherway around?

Hi 597596, I have a couple singles like this with the gum over the printing. It kind of looks like a varnish finish. Trying to find them so I can scan them. Keith

Thanks gkc

Tonymacg, What does you double gummed stamps catalog for? How rare are they?

Gum was typically applied either before or after printing. The timing was determined by the printing process amongst other considerations.

Stamps printed over the gum typically have a rather mottled appearance, like that example from Bhopal (which was printed by Perkins, Bacon - the printers of the Penny Black, incidentally). Here is another example of a printed on the gummed side:



That Charkhari block gummed both sides isn't listed in any catalogue, AFAIK. As the straight two imperf between pairs, Gibbons prices it at £90.

You Have a really nice error collection.

Well, I bit the bullet an sent this block to The Philatelic Foundation to be expertised. I'm hoping it's worth the cost!

I would like to thank everyone for sharing with me. I'll let everyone know in about 6 weeks what I find out.

How does an expert committee come up with a value for error stamps such as this, if it is genuine?

Expert Committees don't usually put values on the stamps they expertise. They just certify the stamp genuine or not, and usually mention any faults they find. It's then up to the market to assign a value.

Makes sence, but how do you know what they will charge for Their opinion? Will they use the standard catalog value?