Watermark: Cornerstone plus on left, same image of the same
Bird, the a bulbul facing left on the right, flipped to face right,and
put on the left of the watermark, darker than background with vertical
5000 lighter than background to its right.
The central vertical stripe with two horizontal decorative hexagons is
clearly visible on issued banknote when you know what to look for
as it is partly covered by printing and the security strip.
Also seen on the Rs1000 and Rs500 notes, but not on lower denominations.
Image of Watermark paper without any Printing was listed on eBay
Auction in 2013 April-May by a dealer in Germany with title
Specimen Watermark Paper Portals (De La Rue).
The Watermark paper of a few Countries were listed which included the
2010 Rs5000 and Rs1000 notes of Sri Lanka.
The Seller said I quote.
It is originally from the banknote designing process from DE LA RUE
(in cooperation with Portals) for elaborating new banknote series.
It is NOT a cutout from a whole banknote sheet; it is a single Specimen
on real banknote paper for the designing process from "the tables of
the designers". Original size like the real note.
It contains the same watermarks and security features as the finally
produced banknote.
You can see that this watermark is still a trial as the security
stripe (which you can find on the real note) is replaced by a special
type of watermark on the trial.
He said in E-mail I bought the notes on a papermoney fair from a dealer. He has contacts to De La Rue who offered him these papers.
I sent a message online to DeLaRue and asked CBSL how security paper is sold on eBay, but got no reply.