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Post by irishjack on Aug 13, 2013 22:41:41 GMT
I was looking over my #4iv and noticed a crack which appears a plate crack on the top right hand corner. Is this common?   |
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rod222
Member 
Posts: 9,907 
What I collect: Worldwide Stamps, Ephemera and Catalogues
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Post by rod222 on Aug 14, 2013 5:03:19 GMT
Not a Canadian specialist Admin, but that crack appears on the images I have in my virtual collection. Common? unable to say. Not mine...  |
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Ryan
Member
Calgary, Alberta, Canada
Posts: 2,721
What I collect: If I have a catalogue for it, I collect it. And I have many catalogues ....
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Post by Ryan on Aug 14, 2013 8:32:40 GMT
Ralph Trimble's re-entry site shows many positions on the plate for this stamp. All of them have the crack you notice. On a large number of them, you can also see a crack that runs from just under the "P" in "POSTAGE" diagonally down through the centre of the beaver's body. The die must have cracked during the process of transferring the individual positions, I would guess. Here's an example image, taken from Trimble's site.  Ryan
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BC
Departed
Rest in Peace
Vancouver, BC Canada
Posts: 836
What I collect: Worldwide USED up to the 1960's, later years from countries that came into existence after then, like Anguilla, Tuvalu and Transnistria.
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Post by BC on Aug 14, 2013 16:54:08 GMT
My 2 copies also have the crack. Actually, it is the opposite of a crack, as a crack would fill in with ink and show a solid colour.
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Ryan
Member
Calgary, Alberta, Canada
Posts: 2,721
What I collect: If I have a catalogue for it, I collect it. And I have many catalogues ....
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Post by Ryan on Aug 14, 2013 22:41:05 GMT
It would have been a crack in the master during the siderography process. The crack would then fail to transfer to the individual positions, leaving an untouched raised portion on the final plate which wouldn't transfer ink. I haven't seen an entire plate's worth of images so I can't guess whether the right hand side crack is there on every stamp, but that crack must have happened very early in the process since every image I've seen does show it. The crack running through the beaver's body doesn't show on every stamp, so it happened farther along. Clearly, the knowledge of the steel hardening processes needed for siderography weren't quite fully developed yet. Metallurgy is weird stuff, mix a bit of this and a bit of that and you can completely change the properties of steel. Manganese is an interesting example. Add a little bit, and the steel gets stronger. Add too much, and it gets so brittle you can turn the steel to powder by beating on it with a hammer. Add a bunch more, and it changes again into something outrageously tough that gets harder the more you abuse it. en.wikipedia.org/wiki/MangalloyRyan |
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rod222
Member
Posts: 9,907
What I collect: Worldwide Stamps, Ephemera and Catalogues
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Post by rod222 on Aug 15, 2013 1:26:05 GMT
Great explanation Ryan! I hadn't figured that. Siderography Transfer Roller:  |
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therealwesty
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Inactive
Sorting my Small Queens
Posts: 331
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Post by therealwesty on Aug 19, 2013 19:59:39 GMT
Of 3 copies I have of #4, 2 have the white line and one does not. I raised this topic in another forum not too long ago and found that the white line is pretty common. It appears on a lot of copies as well as a number of proofs of the stamp.
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watermark
Member
Posts: 62
What I collect: My main collecting area is focused on Canadian stamps printed from steel engraved plates. Specifically re-entries and constant plate varieties.
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Post by watermark on Sept 27, 2016 13:21:59 GMT
Winthrop S. Boggs in his work THE POSTAGE STAMPS AND POSTAL HISTORY OF CANADA states the following: "Before discussing the plate varieties we wish to briefly discuss the well known "flaw" or "cut" which shows on all the subjects of the 3d plate, more or less clearly, especially the fine impressions on machine made paper after 1857. On the proofs this flaw also shows clearly, particularly when in black. The flaw does not appear on the die proofs, and neither does it show on the die proofs of the 5c 1859, the die for which was the 3p die suitably altered. This flaw is therefore a "relief flaw" or "relief break" which occurred on the transfer roll. Since the lines on the transfer roll are raised (that is the relief on the transfer is similar to the finished stamp), it follows that the breaking of any of these delicate lines will result in a "white" line or break showing on the printed stamp. Traces of color may be due to ink smearing across the break and being transferred to the paper during printing. The fact that all the stamps on the plate show this flaw is sufficient evidence that only one relief was used in making the plate, as it is extremely improbable that two reliefs would show exactly the same flaw."
Here is a copy of a diagram of this from the aforementioned book: |
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