Marks On The Back Of The Stamp

Covers are always a problem. And while French expert Roger Calves was a Bundesprüfer, he apparently has signed covers not in accordance with the above rules, perhaps before joining the group. Bundesprüfers also permanently mark types on the back of stamps (some did it in pencil) with their handstamp. That caused a problem when Michel changed around type numbers for some stamp.

Whatever happened to the PF permanently marking stamps they considered forged, started in the 1990s? It was a check-the-box option that apparently few submitters dared to check on the form. That is except for one guy I knew, who decided to "do the right thing" and checked the option on a mint W/F sent in.

It was a type ID of some sort (I remember seeing the stamp and thought it was a slam dunk), and the PF returned it as misidentified, with a black handstamp on the back with the wrong type number. Resubmitted, it came back with a corrected certificate. The stamp now had an almost 1/4" solid black circle over the wrong type handstamp. Needless to say...

Writings and marks on the verso of stamps - it's part of the philatelic fun
To quote Bookbndrbob from a recent post:
"There are collectors of historic stamp dealer markings and ephemera. The stamp is certainly worth more with the marking than it would be without it."

I was shocked to see, on a social media post relevant to my area of interest (Gulf States) that embossing is used by some "experts" to authenticate stamps! I was surprised that no-one else on the thread seemed to regard this as effectively destruction of a possibly valuable stamp.