Just what exactly is a 'plate block'? I have heard different descriptions.

golddustin

When I worked with a very avid (and experienced) philatelist (sp) many years ago, he told me that a 'plate block' was always the bottom right 4 stamps of a sheet, and that the 'plate' position of the sheet had to be the bottom right for the sheet to be a plate block sheet. Is this still the case? I see an awful lot of eBay auctions for 'plate blocks' that are obviously not the bottom right 4 stamps.
A couple other questions - I had been putting away sheets, plate blocks, as well as cancelled stamps that I thought were a bit unusual (for whatever reason) over the last 30 years or so, and I just opened the briefcase that I keep them in about a week ago. I sure did save a lot of stamps! So, I have been listing some on eBay, always checking completed listings to get an idea of value before I list mine. I notice that eBay has a drop down box for types of cancellations - I am not familiar with the proper terms for the different cancellations, other than the obvious - 'flag' for instance. The reason that I kept many of the cancelled stamps was because of the cancellation mark - many are various forms of 'Collect Stamps', but some are pretty unique.
Also, the stamp collector that I knew told me that single cancelled stamps were actually worth more than new stamps, at least for his collection, and as long as they were in really good condition. I wondered if that is still true, or do collectors prefer new, unhinged stamps now?
I'll attach some photos of some of the used stamps & cancellations as examples of what I have. Any suggestions or answers would be very much appreciated.

Chuck

Aethelred

This is a plate block:

Overdate

I collected plate blocks when I was younger (decades ago) and don't recall anything special about the bottom right of a sheet. Plate blocks could be in any position as long as the plate number was present. Some people would collect multiple plate blocks of each stamp in order to get one block of each position.

delistamps

I agree with Overdate. The plate block is a block of stamps that has the plate number in the selvage. How many stamps? It depends on the issue. For many of the classic stamps, the plate block had six stamps. That's because the plate number appeared in the middle of the top or side margin, and a plate block included the plate number single and five surrounding stamps, for a total of six. If you search for a C13, C14, or C15 Zeppelin plate block you will find this.

The C3 airmail had had two colors, red and blue with a plate number of each. The standard plate block for this issue is twelve stamps.

The heyday of stamp collectors (in terms of volume of US philatelists) spanning the 1950's through 1970's found most issues with a plate number in the corner of the sheet. The plate blocks were found in one of the four corners. Which one? When the full sheet came off the press, it was four times the size of the sheet you find in the post office. The same plate number could be found in all four corners: UL, UR, LL, and LR. Then this large sheet was cut in quarters, packaged 100 to a pad, wrapped in plastic and shipped to the post office. Some collectors would look to buy a matching number from each of the four corners.

Your philatelist friend may have specialized in the bottom right corner. For him it was probably visually pleasing to have matching positions on his blocks. (Also, if he kept the blocks in stock books he might have liked placing the smooth edge of the selvage in the slot, instead of leading with the perforations which would be found at the bottom of one of the upper blocks.) That said, there is absolutely nothing that makes a bottom right block more valuable than the three other positions.

Generally speaking mint stamps are move valuable than used ones. There are some first day of issue stamps that might draw a premium, as well as historic covers. Cancellations like the ones you have do not bring a premium.

edited to add: In the 70's the USPS began issuing many stamps that had 4, 5, or more plate numbers, one for each color. For this issues it was necessary to collect a block large enough to capture all the numbers (e.g., five numbers would be a 5X2, or 10 stamp block).