P&R I Early Perforation Varieties

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P&R I Early Perforation Varieties

Notapor rubiera » 20 Jun 2010 18:36

After ignoring this topic for a very long time (try 15 years), and receiving a Stanley Gibbons transparent strip to measure watermarks, I have made some measurements of the 10c Rivadavia Red:

Small, slightly irregular holes:

Type I horizontal.

Imagen

Type I vertical as if it was 13.5, which it isn't.

Imagen

Type I vertical measured correctly, looks like 13.1, and not 13.

Imagen

Type II horizontal

Imagen

Type II vertical

Imagen

Medium, regular holes:

Type II horizontal

Imagen

Type II vertical

Imagen

After these measurements, I now realize why I am unable to separate the two vertical perforations with the naked eye:

1. The 13 perforation is from the irregular grid with small holes, and the measurement is not exactly 13.5 or 13.
2. The difference between 13.1 and 13.4 is VERY small.

I wonder if the other stamps from the first batch (October 1, 1935) are also found with the 'almost 13' vertical perforation?
sitio Ingles/Español de P y R I
http://www.somestamps.com/arg3551/index.htm
sitio general:
http://www.somestamps.com/
blog de P y R I en Ingles
http://arg3551.blogspot.com/
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Re: P&R I Early Perforation Varieties

Notapor rubiera » 20 Jun 2010 18:37

I find the following after looking at some 5c lithograped:

The perforation comb used during the first printing, from October 1, 1935; with small and irregular holes, result in variables measurements of the vertical perforation between 13.1 and 13.4. I only find one vertical row with 13.1 perforation, and it is a row with a skipped perf hole. Here I show three illustrative blocks.

The first block is from the row with a perf skip, perforation 13.15, and it should be the same row as that for the 10c Rivadavia Red type I block shown previously.

Imagen

Imagen

The second block measures 13.3

Imagen

Imagen

The third block measures 13.4

Imagen

Imagen

Judging by the rare frequency with which I find the 13.1 perforation, I am guessing that it is only found in one column of the sheet. All of the 5c lithographed (5c1E1) look like they were perforated with this comb; and not with the later comb that measures exactly 13.5 by 13.5.
sitio Ingles/Español de P y R I
http://www.somestamps.com/arg3551/index.htm
sitio general:
http://www.somestamps.com/
blog de P y R I en Ingles
http://arg3551.blogspot.com/
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Re: P&R I Early Perforation Varieties

Notapor Rein » 22 Oct 2010 19:50

Tony,

The size of the small sized P&R I in offset-litho happens to be

24.0x30.5mm

Once you know that size it is a matter of counting the number of teeth both horizontally and vertically: 16 horizontal, 20 vertical!
The gauge has to do with the stamp size - heart-to-heart from the top row of holes to the bottom row of holes!

Now a simple mathematical exercise:

X : 20mm = 16 : 24mm => X = 32/24 = 4/3 = 13.333333333333

X : 20mm = 20 : 30.5mm > X = 40:30.5 = 13.147

so 13.333:13.147 in 3 decimals

We may 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. The typography stamp in sheet-fed [10c red] also has a height of 30.5mm.

X : 20mm = 20 : 30mm => X = 40/30 = 4/3 = 13.33333333

so 13.333 :13.333 in 3 decimals

Rounding off to the nearest quarter would give 13 1/4:13 1/4 in both cases!
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