A very dangerous forgery can be found on early scarce stamps: the so called Mme Joseph forgery.
It is described in Derek Warboys' book 1994: "Madame Joseph forged postmarks".
In the Goyns-Klinger Postmark book it is marked PU9B as forgery of the original PM4 postmark..

Warboys: PM4 forgery
A forgery of Goyns Klinger type PM4 shown in the Warboys book.
Type PU9B is the most dangerous forgery of a New Hebrides postmark. The impression is always very faint and the 'R' of 'MR' is slightly wider than on the
genuine postmark. It is found with a March date on scarce New Hebrides stamps (mostly low grade copies) and has fooled expert committees. As used examples
of these stamps have higher catalogue values, it was intended to enhance the value of unused examples by the use of PU9B.
Most of the copies with PU9B are badly centered ones which were cheaper to find. MR 25 is the stándard date but sometimes parts of the date are obscured
by placing something between handstamp and stamp. Mostly the year is not present.

SG 35
A forgery of Goyns Klinger type PM4 on a 2d (SG 35). Year slug missing.(Klinger coll.)

SG 35
A forgery of Goyns Klinger type PM4 on a 2d (SG 35) graphically enhanced. (Klinger coll.)

SG 35
A forgery of Goyns Klinger type PM4 on a 2d (SG 35) graphically enhanced. (Klinger coll.)

expertise
(new 10/21)
The RPSL expertise for this stamp. (Klinger coll.)

SG 28
A forgery of Goyns Klinger type PM4 on a 5/- (SG 28). Part of the 5 in MR 25 ande year slug missing.(Klinger coll.)

SG 28
A forgery of Goyns Klinger type PM4 on a 5/- (SG 28) graphically enhanced. (Klinger coll.)

SG 28
A forgery of Goyns Klinger type PM4 on a 5/- (SG 28) graphically enhanced. (Klinger coll.)

SG 35
A forgery of Goyns Klinger type PM4 on a 2d (SG 35). Year slug missing.("SeSi" coll.)

SG 35
A forgery of Goyns Klinger type PM4 on a 2d (SG 35) graphically enhanced. ("SeSi" coll.)
"SeSi" found two interesting forgeries of Goyns Klinger type PM2:

PM2 fake on a Raché postcard
A forgery of Goyns Klinger type PM2 on a Raché postcard

cancel 1
cancel 1

cancel 2
cancel 2

cancel + genuine PM2
cancel 1 with a genuine one in yellow

PM2 fake on a Raché postcard
(new July 2024)
A forgery of Goyns Klinger type PM2 on a Raché postcard. ("SeSi" coll.)

cancel
The forged postmark
The forged cancel has only 18 dots in the small circle. I think the date wants to say 25 MAI 06.
At right a genuine PM2 in yellow placed on top of the forgery.

postmark forgeries
(new July 2024)
Sample of pulls of various pstmark forgeries in Australia. ("SeSi" coll.)

postmark forgeries
(new July 2024)
Sample of pulls of various pstmark forgeries in Australia. ("SeSi" coll.)
The original proof pulls of the BNG, NG, Norfolks Is, NH and NSW hand stamps
found and destroyed in 1946 by the PIXIES (Pacific Island Circle of Royal Sydney Philetelic Club).
The 16 cachets mounted on a Correspondence School (Blackfriars Sydney) Merit Certificate
signed W.FINIGAN Headmaster, well known NSW philatelist in early 20th century and PIXIE member.
(ex Ray Kelly coll.)
Forged G.R.I overprints on German Samoan stamps were on sale in Sydney on November 1914 .
The forger a stamp dealer Milan RAITCHEVITCH was arrested by the police .
At the trial in March 1915 RAITCHEVITCH started that he had never guaranteed that the stamps
were genuine and was acquitted .
There was no mention in the trial of any other cancellers found at his shop .
It would apear that the brass and steel cancellers were manufactured by a skilled engraver
and die-sinker in 1914 .
As Raitchevitch was arrested in November 1914 , he may never have actually used them .
( From an article by Barbera HANCOCK published in Sydney Views May 2014 ).

DE 22 / 1907 forgeries
(new July 2024)
Sample of pulls of the DE 22 / 1907 forgery in Australia. ("Klinger" coll.)
Transcript of the handwriting:
New Hebrides - Forged Postmarks - The Pacific Island Study Circle within the Sydney Philatelic Club has come into possession of some
dies of forges postamrks cut about 1925. The dies were defaced but before doing this some pulls were made to assist in the detection
0f forged postamrks..
This is one of the pulls on crown parchment paper. This forged postmark of New Hebrides is dangerous
especially when found on NSW stamps.
Today (13 FEB 17) I found a similar forgery of GK type PM2: (could be 08 or 09)

PM2 fake on a postcard
A forgery of Goyns Klinger type PM2 on a postcard

fake
Fake

PM2 genuine
Original

fake
Fake -wrong colour image for better cancel visibility
This is a very unusual fake and I have to wonder why it was made. I also don't know by whom and when it was made. The stamp is not gummed.

20 Pounds stamp
(new 7/2021)
a 20 Pounds forgery. (Michel Blanc coll.)
2d on French 40c overprint - watermark RF:
Faked overprint of the 2d ovpt. at a place high on the stamp where it is unknown on genuine stamps. Miraculously this stamp has a 1979 BPA certificate
said the dealer who offered it in the US.

2d on 40c w/m RF
2d on French 40c watermark RF : FORGERY

2d on 40c w/m RF
This is a genuine stamp at least - the cancel however is very dubious.

2d on 40c w/m RF
With a bit of goodwill the cancel could be a 1952-59 PCH Type 16 which is sometimes found as CTO on older New Hebrides stamps.
Forged ANHCo Cancels

ANHCo
Forged Port Vila ANHCo cancel on a 1d stamp
(seen on the Internet)
In the right bottom corner you can see the original cancel in the same position as on the stamp.

ANHCo
A forged cancel which accumulates the differences to the real one:
diameter 19mm, PORTVILA in one word. Date SP (1)0 98. ("SeSi" coll.)

ANHCo
The same cancel with year 97. Offered by Gaertner Auctions Germany in Sept 2011. They
conformed that the lot will be retracted after I pointed out to them that the cancel is a forgery. The left stamps
has traces of an ANHCo cancel in the left bottom corner.
Image thanks to Gaertner Auctions.

ANHCo
This forgend JU ((21 97) cancel.

ANHCo
The same cancel with year 97. (ex Millet coll.)

ANHCo
(new Feb 2018)
The same cancel with year 97. (Klinger coll.)

ANHCo
(new 4/2020)
The same cancel with year 97.

ANHCo
(new 2 March 2018)
Even with a dot matrix printer somebody tried to fake a cancel! ("SeSi" coll.)
In December 2021 my friend "SeSi" found another forgery of the ANHCo "PORT VILA POST" cancel.
Characteristics: Anything you want - not a circle but flat at top,
P(ort) and (pos)T P & T horizontal, "HEBRIDES" too short, no dots at left & right, N & H of "A.N.H." colliding etc etc

ANHCo fake
(new 31 Dec 2021)
A newly found PORT VILA POST cancel forgery ("SeSi" coll.)

ANHCo original
The genuine postmark
In August 2024 I saw a funny piece of an ANHCo 1 Penny local on an auction site:
This is apparently not a forgery in the sense of a counterfeit postmark, but rather, in my opinion, a humorous play, seemingly done with a business stamp from Port Vila. A curiosity!

ANHCo gimmick
ANHCo gimmick

reconstructed
the handstamp optically reconstruccted
Forged Vila cancel on a 5c and 25c NC & a 1911/12 French 5 Fr. stamp. (Klinger & Goron coll.)

VILA forgery
Forged VILA cancel

VILA forgery
Forged VILA cancel

VILA forgery
Forged VILA cancel

VILA forgery
Forged VILA cancel
A couple of snippets made from "Buess covers" - I suppose genuine cancels used on hundreds of covers, maybe produced much later than 1910-11. (all Goron coll.)

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet

BUESS snippets
BUESS cover snippet
Here are some more samples of these:

more BUESS snippets
more BUESS cover snippets

more BUESS snippets
more BUESS cover snippets

more BUESS snippets
more BUESS cover snippets
Curiosities
A couple of these curious BSIP stamps with two different
overprints may exist. It seems that they originated at least from before 1960,
maybe earlier. There is no sign whatever that they have any postal origin. Maybe
they are just a private product in the political jumble of wartime.

BSIP fake
British Solomon Islands Protectorate stamp with forged overprint.
A cover with two British 2d stamps, maybe of the 1921 CA issue, with a red
typewriter "overprint" "One Penny / Halfpenny". Maybe the producer of this
phantasy "overprint" was the same person who typed on a mint pair of ANHCo's (please
see "Pre-Condominium - ANHCo stamps). It is said that the addressee was a prominent collector. The cancel is PCH type 7.

Overprint forgery
Cover with forged overprint.