Centering Of Stamps Question

What causes a stamp to have imperfect margins which results in a lessor desired "centered" stamp

Is it due to the printing process or other?

It is a question of imperfect- or mis-perforation usually.

Peter

Perforating sheets of stamps was typically a secondary process, a process which required the sheets to be properly aligned in the machine to produce a 'well centered' stamp.

Over the decades this process saw a number of improvements including some which were technology based. For example, 'electric eye' marking in the margins of the sheets allowed perforating equipment to better align the sheets and made mis-perfs and/or poorly centered stamp less likely.
Don

Thanks. To further expand my inquiry.

So for stamps produced 1870-1910 as an example, why/how is that some of those stamps are considered very well centered.

I suspect that was due to the "luck" of the production process for that specific stamp.

Am I making sense on that or missing something?

Thanks

To my mind during the earlier period it was not so much about luck as it was the machine operators level of skill and care.

Considering the (seemingly) random spacing between perf rows or columns, part of the answer has to do with the set-up of the perf machines. I suspect the reality was some secret-sauce combo of set-up, skill, and luck. I suspect skill made the difference between a VG stamp and an XF stamp. I suspect luck got you from XF to Superb. A BIG part of it is probably the technology of the day, too. But, hey, what do I know? I think the QA process of the time was: Are the stamps printed on the sheet? Does it have perfs? Pass/Fail. They were aiming for XF (on a bragging-rights basis), but they didn't scrap VG (on a cost basis).

ETA: the above scenario is for the earliest perfed stamps. I think improvements in technology as time went along made the product better and better.

I always thought flat plate stamps were centered better than rotary press stamps. Am I wrong?

Jack Kelley

I am of Rogdcam's mind on this matter: some perforator operators likely were content to come close - do a good workmanlike job - and others took just a little extra time to line things up with a slight improvement in the alignment. Some may also have just had a better visual acuity and hand-eye coordination to do it well and had an advantage.

One might expect this variability to extend uniformly across various issues, but I find it interesting that some issues (speaking of US issues here in the pre 1930 period) appear to have been fairly well perforated, proportionately-speaking, such that many survivors are found that are well centered, whereas other issues in the period seem to have very few well centered examples surviving.

Dealers with long experience get a good perspective on this, and the individual collector can also gain perspective by looking at many offerings on hipstamp, for example. I think we have a substantial advantage now in this regard, compared to pre-Internet generations of collectors, so that the individual collector can gain experience seeing numerous examples of particular issues to realize whether a given issue has proportionately more well-centered examples than another.

I think it will also depend on what era/issue the stamps are.

Some stamp issues were made on paper that was subject to shrinkage. I would assume the perforator would have been set to one-size-fits-all, so atypical shrinkage might cause some stamps to be quite badly perforated.

You can see this effect on sheets of GB Penny Reds, for example -- the margins are not uniform throughout the sheet.

Just to be different, I believe that luck was the most important factor. Production was most likely measured carefully, so there wasn't time to be precise while still making production quotas.

I think equipment was part of this equation. Comb-perfed stamps are much easier to center than line-perfed stamps, the latter more often being well off-center even up to the 1950s. I'm sure there are differences country to country.

This discussion prompts another question. Is there a collection of videos demonstrating how these antique perforating machines operated?

I have found one video of a basic perforator on the Philosateleia.com blog.