All papers used in the manufacture of aerograms are unwatermarked unless
specifically mentioned in the Kessler's Catalogue listing.
All watermarks are illustrated in the catalogue and appear ahead of each listing.
The exception is the standard watermark used for many of the aerograms of Great
Britain and British Colonies, as well as for a few other countries; such as, Ethiopia, India,
Liberia, etc. This standard watermark is the exclusive manufacture of Messrs. Wiggins
Teape & Co. Ltd. of London, England, and reads, "IMPERIAL AIR MAIL" with a picture of a
Gateway (Castle) and a capital letter. This capital letter is usually found below the Gateway and
above "AIR MAIL" in the
design and indicates the year of manufacture of the paper in accordance with the
following code of identification:
|A = 1948
||M = 1959
|B = 1949
||O = 1960
|C = 1950
||P = 1961
|D = 1951
||S = 1962
|E = 1952
||T = 1963
|F = 1953 (reversed)
||V = 1964
|G = 1954 (reversed)
||Y = 1965
|H = 1955
||Z = 1966
|I = 1956
||A = 1967 (letter below "AIRMAIL")
|K = 1957
||B = 1968
|L = 1958
||C = 1969
NOTE: The letters "F" and "G" are always reversed as shown above to avoid
confusion with the letters "E" and "C." The letter "J" was never used and the use of the
letter "N" has been omitted. The letters "Q", "R", "U" and "X" were also never used. In 1967,
the alphabet was repeated beginning with the letter "A". In order to distinguish
this second use from the first, the letter was moved and is now below the words "AIR MAIL" at the
bottom of the watermark.
The capital letter is an integral part of the design incorporated on the dandy roll
which creates the entire watermark in one operation.
The capital letter "L" is known to exist in the normal position, below the Gateway, as
well as directly below the letter "I" of "Imperial." The positioning of this letter is varied on
occasions by the manufacturer.
The management of the New York office of Wiggins Teape & Co. Ltd. has been
most helpful to the editors of this catalogue and has explained to us the following basic
In the manufacture of paper, the watermark is impressed upon the still wet and
pulpy paper by a so-called "dandy roll" before
the final drying process begins, hence the
expression "watermark." At this stage the paper is still quite thick and pulpy. After this
impression, or better said "displacement" is made, the paper travels over a great many
steam heated cylinders. In forming and drying some sheet distortion takes place and the
design created by the devices on the dandy roll, in the wet web of paper, tends to
become elongated. In order to correct this condition, the device is purposely deformed
so any changes which may occur then result in the design appearing in the finished
paper as initially required.
Dependent on the size of sheet to be cut from the finished roll of paper it is
sometimes necessary to watermark the paper with the device falling in the machine
direction and at other times in the cross direction. Although it is the paper maker's aim in
either case to finally achieve similar watermarks, slight variations may be found.
DANDY ROLL: We wish to explain within the limitation of this short space what
a dandy roll is and how the watermark design is created.
The original design in its somewhat deformed state is made by a highly skilled
artesan and formed by hand out of copper wire. The finished design, made out of this
copper wire, is impressed upon wax and then removed, leaving an exact negative
impression. The wax is then covered with a thin film of graphite to make it conductive to
electricity. It is then immersed in a copper sulphate both and an electric current deposits
metallic copper on the graphite surface. Thus electros are made which, of course, have
the same form and thickness as the original copper wire design. These electros are then
carefully soldered upon the dandy roll.
The dandy roll itself is made of metal and fashioned somewhat like a hollow tube,
consisting of an outer cylinder of wire mesh, reinforced at intervals by a skeleton or
It is upon this wire mesh that the electros are soldered at specifically determined
intervals across the length of the roll. Spacing between these electros depends upon the
size of and the desired registration of the watermark.
Specifically referring to the watermarks appearing on the British and Colonial
aerograms where the capital letter changes every year, it is unnecessary to prepare a
new dandy roll, as it is a simple operation to remove the capital letter of one year and to
solder a new letter replacement in its place. This replacement of the letter was
done on January 1 of each year so that all paper produced in the new year would have the
It is known that in very rare cases parts of the devices may have become detached
from the dandy roll during the manufacturing process, which results in an omission in
the watermark. Only three such instances are known, listed under Great Britain, Cat.
No. 7b, and Hong Kong No. 3b and 9b, where the capital letter signifying the year of
manufacture is missing.
Messrs. Wiggins Teape & Co. Ltd. graciously furnished us with original "rubbings"
made directly from the two types of dandy rolls employed. We are illustrating these
original "rubbings" as well as the final design as it emerges from the paper making
machine and as it appears on the aerograms themselves..
Illustration A: This is the original design when placed to fall in the machine
direction. It is shorter in height than the watermark in the finished
Illustration B: This is the original design when placed to fall in the cross direction. It
is narrower in width than the watermark in the finished paper.
Illustration C: This illustration is made directly from the finished paper.
NOTE: Allowances in the size and shape of the watermark in the finished paper will
have to be considered because of uneven shrinkage and other causes.
The letter "B" has
been drawn in in all illustrations for the sake of uniformity.
This code, utilizing capital letters to indicate the year of manufacture of the paper
originated in 1948. Messrs. Charles Morgan & Co. Ltd. of London used the same
system in their paper for the aerograms of Southern Rhodesia, watermarked "Kent Vale
Parchment." The only earlier watermarked papers of this concern are:
"KENT VALE PARCHMENT-W 2", mode in 1942, used in 1944 for Southern
Rhodesia No. 1.
"KENT VALE PARCHMENT-7", made in 1947, used in 1947 for Southern Rhodesia
This same concern, Charles Morgan & Co. Ltd., also supplied the paper used
for the aerograms of Ethiopia, watermarked:
"WROTHAM VELLUM WOVE-KENT-A", made in 1948 and used in 1951 for
Ethiopia No. 2.
UNWATERMARKED SHEETS: The majority of all aerograms are printed on paper
without any watermark, but even among sheets which normally are watermarked, there
is found occasionally a sheet entirely without any watermark. This occurs in the die
cutting of the individual sheet and is dependent upon how closely the watermark is
spaced on the original paper. If widely spaced, more unwatermarked sheets are found.
These, when known, are listed as a minor variety.
INVERTED WATERMARKS: A watermark cannot be inverted, as it is the first
marking the paper receives. Only the printing can be inverted or sideways. Because
there are numerous possibilities in the position of the watermark in relation to the
printing, we have made no attempt to list or even verify them.
DEFECTIVE MARKS: Only one such case came to our attention, where the letter
"P" of "Imperial Air Mail" is considerably indented. It is a constant variety and occurs on
sheets of Hong Kong.
GREAT BRITAIN WATERMARKS: All aerograms printed on blue paper and
bearing Tablet B-l are normally watermarked, whether they were issued for Great Britain
or any of the Colonies. Of all aerograms of Great Britain proper
, this watermarked blue
paper exists only with Tablet B-1. All other aerograms of Great Britain With other tablets