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The stamps printed in offset-litho and in flat-bed typography were perforated on a separate machine using a perforation head out of the several standardized sizes. The philatelic convention of denoting perforation gauges not more precise than 0.25 gives way to hardly manageble 13 1/4:13 [after the sheet-fed printing aplied on the aseparate machine] and 13 1/2 [applied in-line on the Goebel press]. Pettigiani says that the pins of the 13 are positioned irregularly and are thicker whereas those for the 13 1/2 are thinner and more regular. What does not get mentioned in the book is that there are only 2 instances of stamps having been printed both on a flat-bed press and on a reel-fed rotary! These are the 10c Rivadavia red and the 40c José de San
Martin red on matt paper. This 40c stamp from flat-bed plates has a 13
1/4:13 perforation and does not get any recognition in Argentine
catalogues.... Merlo does mention this very explicitly in his
excellent book Why not read the Argentina classics??? And profit from them! |
| ... In order to estimate the perforation
gauge you need to know the "official" size of the stamps! And in the
case of the small sized P&R I this happened to be 24.0x30.5mm
Once you know that size it is a matter of counting the number of teeth both horizontally and vertically. In the previous posting I had done so: 16 horizontal, 20 vertical! Now a simple mathematical exercise: X : 20mm = 16 : 24mm => X = 32/24 = 4/3 = 13.333333333333 [in short 13.33 or rounded off to 13 1/4!] X : 20mm = 20 : 30.5mm > X = 40:30.5 = 13.147 [also rounded off to 13 1/4!] The 13 1/4:13 in the previous postings can not be good! |
| .... As I have pointed out in the previous
posting, the gauge has to do with the stamp size - heart-to-heart from
the top row of holes to the bottom row of holes!
And indeed we have 30.5mm for the offset-litho printed stamps that usually have a comb that moved from left to right or vice versa! But for the 13 1/4 perforation we need to look at the stamps in typography printed on the Goebel reel-fed press! The average height of those stamps is NOT 30.5mm but 30.0mm :) [b]We have to re-read Leopoldo Tenorio Casal! [/b] X : 20mm = 20 : 30mm => X = 40/30 = 4/3 = 13.33333333 [or rounded off 13.33 or 13 1/4]. So far we can not rely on our perforation gauges as long as they only provide us with the nearest quarter! |
| ... All we have to do is to measure the
height of the stamps - heart-to-heart of the perforation holes!
and this suggestion and advice I would have expected from Pettigiani! Since 1935 only 2 stamps in typogrphy had been printed both on the reel-fed Goebel and on a sheet-fed / flat-bed typography press: the 10c Rivadavia in red in type II and the 40c José de San Martin. The main difference - to be measured - is the height of the stamp provided there are NO correction teeth! The reel-fed stamps have a height of 30.0mm, the sheet-fed stamps have a height of 30.5mm:
The right hand stamp also has a watermark turned 90 degrees: http://foro.filateliaargentina.com.ar/viewtopic.php?f=2&t=2124 I was hoping to find some reference to the manufacturer of the perforation machines. Pettigiani mentions the name Hogenfonet which does not sound like anything... Searching the World Wide Web did not give any results... Famous manufacturers were Grover and Bickel. Both have been merger into WISTA now.... |
