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 Post subject: Cylinder number offsets
PostPosted: Sat Jul 21, 2012 7:00 pm 
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Joined: Sat Sep 19, 2009 6:00 pm
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G'day all,

Can anyone explain to me how cylinder number multiple offsets occur?

I can understand how a 'normal' offset of a stamp occurs but in this case multiple offsets of the cylinder number occur all up the margin of the sheet.
If it caused in the normal way then there should, presumably, only be the one offset but as the scan shows these are duplicated up the sheet margin.

Any help would be greatly appreciated, bearing in mind that I am a bit of a dumb cluck when it comes to printing processes in general.

Regards to all

Ron.


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 Post subject: Transfer from previous board: original post 2160
PostPosted: Sat Jul 21, 2012 7:05 pm 
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Hi, Ron,
It looks to me that your offsets are at 3-row intervals. That means to me that the perforating head picked up the still wet ink from the margin and - as the perforator comb moved up the sheet - it deposited an impression of the heavily inked cylinder number at each strike of the comb head. The control number wasn't offset because the impression wasn't as heavily inked as the cylinder number.


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 Post subject: Transfer from previous board: original post 2162
PostPosted: Sat Jul 21, 2012 7:10 pm 
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Hi Harvey,
Many thanks for that response.
As mentioned I am pretty clueless regarding printing methods and I am sassuming from your reply that the perforator comb moves up the sheet in 3 row strikes.

Your comments would also explain why the offset gets fainter as it moves up the sheet.

That's great, many thanks
All the best
Ron


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 Post subject: Transfer from previous board: original post 2163
PostPosted: Sun Jul 22, 2012 7:00 pm 
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Posts: 150
Dear Harvey and Ron,

Harvey's explanation seems to be the logical one, and perhaps even obvious, and if there is no alternative explanation then at the least we have to accept it. BUT, I'm left with an uneasy feeling.

What I infer from what Harvey has written is that the cylinder number only, no other part of the pane, has been over-inked. The sheets come of the printer and are stacked. Then seven at a time they are placed into the Type 5 perforator… Then the perforator picks up some of the wet ink from the cylinder number and deposits it as an offset that, as Ron says, weakens with each impression.

Fine, but I find it rather extraordinary that the over-inking is restricted to the cylinder number alone.

I have five pieces from Cylinder 10 of the KE8 ha'penny Green, all showing the offset number 10. Three of these are from the stop pane and two are from the no stop pane. One piece is two stamps wide by 13 stamps long. The lower two gaps between the offsets are 51mm while the next two gaps going up the margin are 50mm. two stamps measure 49mm, while three measure 72mm. One of the pieces is a mild dry print, If the ink in the cylinder numbers remained wet long enough between going on to the sheet and going into the perforator, why are there no normal offsets, from a wet surface onto the gum of the sheet on top of it? There are no normal offsets at all.

Sorry folks, please either explain where my logic and examples are wrong, or present another explanation.

Best wishes,

Robin


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 Post subject: Transfer from previous board: original post 2165
PostPosted: Sun Jul 22, 2012 7:05 pm 
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Joined: Sun Nov 11, 2007 7:00 pm
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Robin/Ron,
Perhaps I explained myself badly. It wasn't that the cylinder number was over-inked, merely that if you look at any cylinder number it immediately becomes apparent that it has been hand-engraved, in comparison to the control number which has been etched in the normal way. That is what makes the cylinder number hold more ink than the rest of the cylinder impressions, including the control.
As Ron failed to show the full length of the sheet in his illustration, I had assumed that that sheet was perf'd by the 2-row type 5 comb was used. Looking at Ron's illustration again, I can see that the difference in the gaps are all 2-stamps high, which confirms the 2-row type 5 comb. If Robin, or anybody else, can think of any other cause for this type of
variety I'd be pleased to hear of it.


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