Belgium 1861 - 1c Green Imperf

I'm wondering whether anyone might be able to identify the specific variety of this Belgian stamp (which forms part of the Belgian collection I'm offering here for trade): 1861 - 1c green - imperf - no watermark.

I also wonder if anyone is able to decode the inscription on the back of the stamp.

Here are scans of the front and back:











Any and all assistance greatly appreciated!

Hi again Jimjamtwo

The marking on the back of the stamp you have scanned appears to be an expertiser's marking.

You might want to try the following urls:

http://www.filatelia.fi/experts/areasa.html

http://www.filatelia.fi/experts/

Hope this helps

Chimo

Bujutsu

It wouldn't surprise me if this were an expertiser's markings as this particular stamp seems to be quite valuable and could still, depending on a determination of its exact shade, be worth around $500-600.

However, I wasn't able to find any clues as to the expertizer's identitity on filatelia.fi. Alternatively, is it possible that some stamp dealers marked the items in their inventories? In this case, there seems to be a number (500?) and a date.

Another question: could this stamp possibly be on laid paper? On the reverse you can see oblique lines in the darkest area of the stamp. I can see no explanation for this other than that this is on laid paper.

Looks woven to me.

You can't see the diagonal lines, rod222?

The lines I see seem only to appear on the printed area of the stamp. I suppose if it were laid paper, they'd go right to the edges.