Need Help / Education On GB Penny Red

I generally don't collect GB and have little knowledge in this area. I came across this stamp and notice when looking at other examples that there are different letter in the lower right and left corners and would appreciate learning what they represent and any other information on this stamp.
Thanks in advance for any help.

The check letters can be used to find the position on the printing plate. You can see your CI can be seen 3 down and 9 across. A complete sheet of 240 is below...


Other information on the stamp depends on various things... watermark, alphabet (the check letters on different issues use different shape and size of lettering).

see my ebay listings many examples of penny red stamps on covers

So this stamp would be position 3-9?

The plate position would be C I . 3 down and 9 across is just my way of saying where to look

Thanks...I understand now...I follow the position C I
Appreciate the clarification.

Looks to me to be a Scott#20...white paper...watermark Large Crown... Perf 14... which would date it as 1857.

A Scott# from someone in UK

Area66, take a deep breath it happens. scotzm, thanks for the ID!
Appreciate the information.

What means Scott #?

"What means Scott#?" I think he was surprised that someone from the UK is using a Scott number rather than Gibbons.

Steve

Apologies - that was my dire sense of humour again, I'm afraid.

Geoff

Good day to all..some information might be helpful..the plate numbers are engraved on the left or right side within the lace work on penny reds..you may need to look at with scope carefully,since sometimes hard to view .( plate number ranges between the numbers 71-225). Price range on penny red covers may be considered more valuable depending on different factors.
Certain plate numbers are very difficult to find including high demand due to being scarce which makes them valuable.For example, plate numbers 69,70,75,126,128..and of course the rarest one of all the plates could be worth in thousands..(plate number 77.) If you find plate 77, make sure get an expert views it to certify that the stamp is genuine.
Best wishes on your penny red's collection!

Blazenstar

"the plate numbers are engraved on the left or right side within the lace work on penny reds."

This does not apply to the stamp in question which is Scott #20. Only Scott #33 onwards have the plate numbering as you describe.

P.S. The plates are known from year 1864. There are 39 plate numbers are known as imperforated..Plate #116.is a great stamp to have

blazenstar

Unfortunately, only the later line-engraved issues with letters in all four corners show the plate number on the stamp itself. Back to hard work for the earlier issues, I'm afraid.

Geoff