2 Different Plate Numbers In One Sheet

Isn't there just one plate number in a sheet? This one has two different plate numbers in the same sheet. Is this normal?

Even though the perforations match rather well, you have a block of 4 on the left, and block of 6 on the right, from two different panes.
Correct, there is one unique plate number per plate.

Yes, indeed, I see it now, too. The cover is not mine but I copied an eBay offer. Thank you for opening my eyes

I agree with John. You can also see a difference in the spacing/size of the perforations at the bottom of right hand side of the block of four and where meets the bottom left hand side of the block of six.

sigistenz, This is a confusing question "Isn't there just one plate number in a sheet? "

Don't you really mean, "Isn't there just one plate number in a sheet for a stamp printed in one color?"
There are many U.S. stamps printed with more than one plate number in the margin, usually in adjacent stamps' margins (with a few exceptions). Also, for most modern U.S. stamps, there is also "one" plate number when there are more than one colors.

Thank you for this addition. I do not collect plate numbers but in this case it struck me to see two different plate numbers in what I saw as one block.

Nice "philatelic" cover!

That is a very interesting and nice looking cover!

Is this cover genuine at all? Were there still fancy postmarks in use in 1928 (issue of the postage stamps)?
Didn't registry require a different marking than that on the cover?

I have no reason to doubt the cover is a genuine philatelic cover.

There was a revival of fancy cancel designs in the 1920s-1930s. See this large price list of 20th Century Fancy Cancels for some other nice examples.

https://hgitner.com/collections/us-...vers?page=15

Additional markings such as the city and date stamp are on the reverse of the cover, as per P.O. policy at the time. Do you have a picture of the reverse of the cover?

Thanks for the fast reply. See the backside of the envelope. It is postmarked MONROVIA, CAL.
What does a letter from Arizona to Kansas do in California?

Because the sender and/or receiver are stamp collectors and wanted the letter postmarked with that fancy cancel from Monrovia.

One way would be the sender mailed the original envelope inside another envelope that was addressed to the postmaster in Monrovia to request the special cancel.

This is often how early FDCs, FFCs or other event covers were created. The collector did not need to travel to each city to get the special postmark themselves, they mailed the self addressed stamped envelopes to the postmaster in that city with a note like "please postmark these with your special XYZ cancel on this date ...", and in those days most postmasters were happy to oblige, and if requested the postmaster would even autograph the covers themselves.

Now that we know the negative star cancel is from Monrovia CA, here are a few others with that same cancel. The first example has a return address of E.P Gibson in Stanton Mich, mailed to himself in Michigan, via Monrovia CA. The second is from Kansas City MO to Elkton KY, via Monrovia, etc.

For anyone who wants a deeper dive, here is an article about "Prescott Arizona's Fancy Registry Cancellations" that gives a brief history. The article is written by A.W. Bork himself, the person named on the return address of your original cover, and who was a post office clerk in Prescott AZ and avid stamp collector. (The article starts on page 13).
https://postalhistoryfoundation.org...graph3-3.pdf

The above article from the Western Postal History Museum Heliograph Summer 1989 explains, "Why had these fancy cancellers come into use exclusively on registered mail in the 1920's? In 1922 the Post Office Department ordered all postmasters to stop the use of any kind of cancelling device which would show the name of the mailing office on the face of a registered letter (or other article). It was felt that greater security would be provided if all mail handlers were forced to check the number on the face of the letter and the mailing office's backstamp on the back flaps sealing it. Seemingly there had been much tampering with such mail en route."

So these registered letters likely did not contain anything of value, they were sent Registered because that was the only way that these particular postmarks were used.


Edit: fixed spelling and added page number of the PDF where the Prescott article starts.

Thank you very much, ZebraMan for all that work to enlighten me sucessfully.
I bought the cover, it is still in the mails on the way to me. Together with the sender's article including even his contemporary photographs this makes a nice juicy story.
Such is the essence of stamp collecting, rather than just accumulating.
Thanks again and have a nice day

Recently I could acquire a block of 4 Scott #702 with 2 diff. plate numbers and I know now, why: 2 plates were necessary one for the black, the 2nd for the red. In my old (2004) this is valuated a dash ( - ). Because of the limited market as is said in the introduction.