Great Britain Stamp, Sg#: 212 ,1 Pound ,1891- Control Number At Right Corner?

This ,Great Britain stamp, Stanley Gibbons #: 212 ,1 pound ,from1891 has a very unusual green ink feature on the lower right corner. Wath could be the reason, for it's presence there. Could this be part of a control number or letter on the original sheet?

No, this stamp never had a control number.

There may have been some foreign matter on the plate that caused an ink spot.

Those cut perforations at the lower right are suspicious.

edit: There would have been a stamp with check letters TD to the right. So, there could never have been any sheet margin printing in that position as there only was a sheet margin at the foot of this stamp.

Is that a cleaned cancellation at the top?

You mean at the centre? You might be correct. The frame there and near the 'G' in postage sure look like someone has done something with it.

@post_pe, does this stamp have its gum?

Yes, that's it - possible ink residue around the "T" of postage, then the surface-wear in the "AG" area.

The reperf job at the bottom is actually quite amateurish.

Might that be an "S" as the start of "souvenir" or some such thing?

Anyone have a Vol. 1 Specialised close at hand? I won't be back with mine for more than a week. I'm wondering if C - T is a valid letter combination? (T seems sort of high?)

ETA: I do see a lower marginal C - T elsewhere on the web, so, probably a dead end.

My used version of this stamp is D-O, but no marks such as this one has. Also, I notice a dot on the left side of the OP's stamp:

Picture/scan of the back, please?

@Partime: DO is not a check-letter combination that is genuine. Are you reading left, top to bottom; i.e., did you mean OD?

@cjd,

The height is the same as that for a normal stamp, the width is three normal stams. So 20 x 12 (AA .. TL) becomes 20 x 4 (AA..TD). There is a horizontal gutter between rows 10 and 11 (J and K).

Always read letters from left to right at the bottom. TC is a valid combination.

I guess I wasn't reading this correctly. Bottom first would be OD.

Nice. Yes, that is OD, row 5 of the lower pane, fourth stamp from left (and last stamp in row).

First, you need to test for genuineness. And that is whether this has a genuine watermark or not. There are fake watermarks printed in white or in oil that are incorrectly shaped on forged stamps. If you don't have an accurate reference for the watermark, please post a view of the stamp in watermark fluid.

The dirt at top is just that, typical grubby stamp collector paws hinging the stamp in an album at one time. You see this often enough. It might be removed with careful use of a soft eraser like a Mars Staedtler one.

If you compare with Partime's used stamp, alignment of perf holes is not perfect for this stamp. The hole size and spacing (but not alignment) matches top and bottom on the OP stamp from what I can see. If the stamp is genuine, then the perfs are okay to me.

Still, let's establish whether this is a genuine stamp or not first.

It is not about the hole alignment or spacing. The perfs exhibit no fibers from being torn which could lead a skeptic to state that the simple answer is scissor cutting. It would have to be one crazy pair of scissors to make that wavy-gravy line. No, the perfs are not OK by a long shot.

They are cut at the bottom and not in a straight line. The cuts are reminiscent of those you see on stamp books and coil stamps. Those are cut with a blade. If the bottom of the stamp had been cut with a blade or guillotine cutter, that waviness would not have been there. The leftmost perforations at the bottom are torn.

There, definitely, is something strange about it. The size of the stamp, only, would allow for reperforating if it had been part imperforate between stamp and bottom margin. That would have been a bad decision.