Detecting overprint forgeries
 

Are there ways to date overprint on a stamp without damaging the stamp?
I need to be able to tell if the overprint on a stamp is of the same
age as the stamp, going back say 80 years ago.

Detecting overprint forgeries
 

On Sun, 07 Sep 2014 03:02:32 -0400, Bassem Medawar
sharpened a crayon and wrote:

Are there ways to date overprint on a stamp without damaging the stamp?
I need to be able to tell if the overprint on a stamp is of the same
age as the stamp, going back say 80 years ago.

Age is a 'destructive' process, needing a sample of the overprint's
ink. If you really know your overprint, then visual differences under
a stereo microscope could become apparent.

Gloss, colour, quality of the strike, etc. There should be sublte
differences between the real font used, letter spacing, etc. and the
imitation.

On -=used=- items, it's a bit simpler. The stereo microscope will show
you whether the overprint is under or on top of the cancel. Most of
the GB forgeries used real stamps, from real postings, but of course
with the overprint applied later, it rested above the cancel's inking.

Detecting overprint forgeries
 

I had often heard of the microscope method and did understand how it
applied (beyond the obvious). However as you mentioned *stereo*
microscope I got the point. Thank you.

Sometimes forgeries are so gross that you don't need a microscope.

The type of forgeries I am looking to detect are overprints on French
stamps used in french colonies after WWI. The overprints included many
errors - sometimes created on purpose. So one needs some kind of
instrument to tell contemporaneous variations from modern forgeries.

The under/over method on used stamps is nice. In fact the cancel on top
of the overprint can help establish a comparison baseline for the
overprint on mint stamps.

Thanks again for your response.

bassem

On 9/7/14, 9:42 AM, Sir F.A. Rien wrote:
On Sun, 07 Sep 2014 03:02:32 -0400, Bassem Medawar
sharpened a crayon and wrote:

Are there ways to date overprint on a stamp without damaging the stamp?
I need to be able to tell if the overprint on a stamp is of the same
age as the stamp, going back say 80 years ago.

Age is a 'destructive' process, needing a sample of the overprint's
ink. If you really know your overprint, then visual differences under
a stereo microscope could become apparent.

Gloss, colour, quality of the strike, etc. There should be sublte
differences between the real font used, letter spacing, etc. and the
imitation.

On -=used=- items, it's a bit simpler. The stereo microscope will show
you whether the overprint is under or on top of the cancel. Most of
the GB forgeries used real stamps, from real postings, but of course
with the overprint applied later, it rested above the cancel's inking.