Tilt

A fairly new philatelic term that describes the average tilt of a stamp when compared to the average course of it's perforations. As far as I understand, this useful observation is thanks to the sharp eyes of people like Mike Williams and Brian Perritt, from whom I have extracted much of the following information. They are not responsible for any errors.

A description of how this phenomenon occurs is in order. The perforation machines at Somerset house were state of the art and custom built by Napier for the sole purpose of perforating sheets of stamps. The machines themselves and especially the perforating combs that did the work were absolutely straight and square. Perkins Bacon had been printing the 1d and 2d for many years without any consideration for perforation, since initially (up to about 1850) it did not exist, and latterly, they almost certainly wished it didn’t. The problems that Perkins Bacon subsequently had to face with stamp perforation gave them headaches for years to come.

The process of transferring impressions from a roller die to a plate was initially done by eye and guides marked on the plate. Thus the layout of a plate could be, shall we say, a bit squiffy. This does not take away from the skill of the engraver in any way, the end result was in fact welcomed as part of an improvement in the postal system for Britain. After all, any minor inaccuracy could be made good by the careful alignment of a pair of scissors. But! When this modus operandi met with Napier's perforating machines, there was bound to be trouble.

When Archer started to rattle the cage of Perkins Bacon around 1850, he got a cool response, and maybe even some corporate sabotage, because they knew that their system would have a hard time fitting in with Archer's new fangled machine of holes. Eventually, they had no option but to try to up their game and make their printing plates match the rigid parameters of the perforating machines used at Somerset House. They only really succeeded in doing this with the introduction of the Holtzapffel ratchet gear around 1868 [Check from which plate alignment changes].

Considerations of “square and true” when laying down a new plate.

Was the plate square on the transfer roller table?

Was the impression on the roller die square?

Was the roller attached to the table set up truly square to the plate?

Did the roller slip during the days engraving, and did it need re-setting?

Did the engraver finish the plate in one day? Until the introduction of the Holtzapffel equipment, I would hazard a guess that the answer was “not necessarily”

If the work was spread over more than one day, was the plate and roller set up in exactly the same positions as the previous day?

Lets be realistic. There must have been some inaccuracies in laying down the plates. And there was. And here is the thrust of this page: Inaccuracies in laying down a plate, tended to remain constant within that plate. (One days work). Thus, if “AA” was rotated 1.5* anticlockwise in relation to the side of the plate, then it would follow that all of the impressions on this plate would also be rotated 1.5* anticlockwise. When a sheet printed from this plate was passed through the perforating machine, there would generally be a 1.5* difference between the side of the stamp design and the row of perforations.

Here is a complication. The above result is not a hard and fast rule, the best that we can say is that this result would generally be the case for this plate, since there is another level of man made error to be added into the equation. Each sheet had pinning points marked on them in the form of dots, lines and/or crosses at the top and bottom of the printed sheet. These were engraved on the plate itself, so they would have been consistent. There were instances where the pinning marks were slightly out so would have altered the tilt of the perforations for that plate. The major problem was that the sheets had to be pinned by hand, and so if the pin was a mm out, the tit of the stamp in relation to the line of perforations would be altered. This was complicated further by the fact that sheets were perforated in batches of 5 – 7 sheets thickness, so that what may appear fine and dandy on the top sheet, may have hidden inaccuracies further down the batch. It is also a real possibility that the boys doing the pinning realised that such and such a plate had a bit of a tilt, and if they corrected this by pinning slightly left of the marked point, it came out nice and square. Thus we cannot rely on tilt as being a constant. The best we can say is that such and such a plate tends to have a slight tilt.

CCW = Counter Clock Wise

CW = Clock Wise

This is an incomplete list, and I know that there possibly are inaccuracies in it that need to be corrected. Please do not rely 100% on this. But it is a start.

C1-C2

Strong CCW tilt: 155,157,163-4,167,169-172,175-180,182-4,186-9,194-8,200-1,R3 & R6.

Slight CCW tilt: 162,165-6,173-4,181,190-3,199,202-3,R1 & R4

No noticeable tilt: 185,204 & R5

Very slight CW tilt: R2

Rises rather than falls, i.e. from the top right of a stamp to the top left of the next. stamp along.

166, 203, 204, R2.

C3-6

C7-13

CCW; 34-36, 61-64.

No noticeable tilt: the rest.

CW: 55, 58-60, 65-68.

There is another point. Feeding the sheets in inverted may have messed up the above readings. Just saying.

AP

August 2014