Question On 2¢ Wf A140

I checked the matrix on Stamp Smarter for this perf 11, which I think is type I. Since it's 19 x 22.5 I presumed it was rotary, but that doesn't fit the options, so it must be offset? But that doesn't work either so I must have the type wrong, but the others don't seem to fit. Help please!

Your stamp is not one of the offset prints. It doesn't have the "look" of offset.

Please show the entire mail piece as often the cancel date is a useful clue to rule-in or rule-out certain possibilities.

Your stamp, if indeed perf 11, is either 461 or 499 depending upon whether or not it is single line watermarked (461) or is not watermarked (499). Judging by the color it is 499. Both are flat plate printings.

Here you go!

This late use, it has a 99.9% chance of being a 499, and not worth ruining a nice cover to check for a watermark.

What I don't understand is how it is flat plate at 22.5, with a digital MM caliper.

Forget measuring the design. Paper is hydrophobic. It absorbs and desorbs water. And we are talking fractions of a mm in some instances. Frankly, I wish that those measurements were left out of discussions and used only by expertizers. They just tend to muddy the waters.

Thanks for the help. I've been making the measurements a key part of the assessment, but for this series that does not work.

This tool walks you through the correct steps for IDing these stamps (Design Type - Denomination - Perf - Watermark - Printing Type - Variety).
https://stampsmarter.org/features/S...rank_ID.html

More info on IDing different printing press types here
https://stampsmarter.org/learning/M...methods.html

And much more ID info can be found here
https://stampsmarter.org/1847usa/1847Home.html

Don

An aid to determining flat plate from rotary is to use a gauge. I have used this one for years (left side of gauge). It is transparent and is placed over the stamp, aligning with the frame line of the stamp. Usually accurate, with the occasional uncertainty. But it helps narrow down the ID.

I agree that stamp design tolerances (some within the booklet stamp range) combined with the difficulty of trying to measure accurately makes this the absolutely LAST criteria that anyone should be using to determine the ID of these stamps.

I think that folks gravitate to trying to use dimensions because they side-step having to learn how to determine printing type and seem more definitive. I would remove these design dimensions from Stamp Smarter but when I tried this, I got a lot of complaining that the site was 'incomplete'.
Don

Thanks! So I've learned through this that, due to water absorption, a flat plate can expand to 22.5mm, which is only 2.2% of its height. Due to water loss, perhaps it will shrink a similar amount. I'm learning a lot on this site!

Thanks, Germania. I found a used Phil—Meter on eBay. Hopefully, it will do a better job than what I have been using:

To illustrate just how much variance there can be when measuring stamp designs, consider this; you can find up to a 1mm+ design variance in the US OXF1 Postal Registry Seal stamp.
http://goscf.com/t/76973
This stamp was printed from a single plate, so plate differences can be ruled out. Catalogs and experts say it was printed on a single type of paper, so paper type differences can be ruled out. Yes, the OXF1 is a large stamp but the significant design size delta should give pause to anyone thinking about measuring design sizes.

Luckily, IDing a OXF1 is easy because there is only one major catalog number. I am a retired engineer, and I would love nothing more than definitive ID criteria that could be measured. But measuring W/F stamp designs is the very last thing that should be used to determine an identification.
Don

Without being an engineer.

I use the Sonic Imagery Labs "Precision US Specialty Multi-Gauge". As can be seen, there is a section for Rotary Press, Schermack and other perforations, and a nice sliding perforation scale. It is clear and can be put over stamps on envelopes also. (Only part of it shown here.)