Mexico - avant garde printing techniques - 1916-now

[Rein]

The 1923 version has it:



but also the 1934 definitives have this watermark with the "yellow line" vertical!






to be continued ...

[Rein]

The 10c Intrega Inmediata in both cases with watermark "Mexico Correos" running from bottom left to top right but in a different lay-out:


Letters the same vertically - see yellow line:



Letters the same horizontally - see yellowline:



to be continued ....

[Rein]

In 1940 the watermark with the "yellow line" horizontal was common:






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[Rein]

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[Rein]

to be continued ....

[zakur]

Very interesting that uneven perforation in Mexican stamps...

[Rein]

Great thread Rein, you do some fine research.

I have a question. The Liechtenstein ones below from 1920 were engraved using copper plates (as stated in Michel) and look similar to the Mexican one.

Did Mexico also use copper plates ?





They really don't look like typical engraved stamps.

They were not engraved!

As far as I can follow the French explanation - in "50 Jahre Liechtensteinische Postwertzeichen 1912-1962" (Vaduz 1962, Selbstverlag der Fürstlichen Regierung) - they were photomechanically reproduced and then etched!!!!

to be continued ....

[Rein]

It all sounds like photogravure with a flat plate instead including the photochemical etching!

[Rein]

Making of the plates

Stamps of the Coat of Arms stamps of the Principality


The coin without the value indication and without the frame lines had been engraved by professor Luigi Kasimir on a lithographical stone in a much larger size [55mm x 80mm].

The result viewed by eye does not consist an exact reproduction of the adopted coin, hence the minor differences observed above ....

From this lithographical stone a minimum of 700 reproductions had been printed. On all of them, in the upper left corner (i.e. at the right in direct reading) the initial "H" was placed [H for Heller, the currency used] and after that the various values were inserted in the upper right corners (i.e. at left in direct reading).

The reproductions grouped per 100 [10x10] were photographed decreasing the global surface so they would match the size for printing the stamp sheets.

Total size - from frame to frame - 230mm width, 340mm height.
Total size - the copper plate - 266m width, 388mm height.

So we have 7 photographical plates with which the copper plates - needed for printing - were photochemically engraved on copper.

The photochemical process - The flat plate of copper was cover with a layer of an emulsion consisting of bichromate and arabic gum; the photographical glass plate was placed on top of the emulsified copper plate; the surfaces of the two plates were drawn vacuum to have a perfect contact. Together they were exposed to a strong light source making the emulsion of the copper plates insoluble in water. After the developing in a mixture of lactic acid and glycerine, the metal was exposed and a first acid etching followed.

After the first etching with acid, the layer of bichromate was endorsed with a layer of lacquer by rolling over, then it was heated in a oven to dry and after that several acid etchings followed to receive the ideal depths.

Professor Luigi Kasimir was in technical control at the premises of the Paulussen Printing Works in Vienna.

..........

[Rein]

The brown fibers we met in English paper [Wiggins Teape] in the period 1936-1944 used for Argentina stamps must be present in stamps elsewhere where stamp printing houses use the same manufacturer of stamp paper!

It is a matter of research and some luck as it apparently still is an impossibility to find these brown fibers by Argentinean philatelists!

A few Mexican stamps!

1938 5c plan de Guadelupe






The blue lines indicate the symmetrical wire; the red lines the direction of the line "Correos Mexico"

to be continued ...

[Rein]

1938 10c Housing Congress






The blue lines indicate the symmetrical wire; the red lines the direction of the line "Correos Mexico"

to be continued ...

[Rein]

The 1934 definitives:






The same pattern as in Argentina!!!


to be continued ...

[Rein]

The 1937 definitives in rotogravure:





The same pattern as in Argentina!!!

Rotogravure was the printing method derived from photogravure in which there was not screen! This method was developed by the Nederlandsche Rotogravure Maatschappij [Dutch Rotogravure Company] in Leiden, my home town!

No screen!

[Rein]

Most commemoratives issued after 1938 and printed on the first Goebel photogravure press are in screened photogravure!

However, the stamps issued on May 16, 1947, for the International Stamp Exhibition in New York has UNSCREENED photogravure!

[Rein]