This is one of the most interesting pairs of moulds in the collection and a fine example of the mouldmaker's art of watermarking.
Whilst it is common to have a deckle fitted with a divider to produce two sheets on a single mould, multiple divisions are rare and I have very few to make four sheets. I have never seen another 4 sheet mould illustrated in another collection - please send me a copy if you have one.
The customer is the upmarket bank of Coutts & Company which still has the Queen amongst its customers and whose head office is in the Strand in London. In this case though the watermarks are for Coutts et Cie Banquiers, Strand, Londres. My assumption is that these were to print French bank draft forms for London customers dealing with francophone countries.
Each of the four elongated sheets would have folded in half for binding. Hence one half shows the watermarks forwards and the other half in reverse so that they would all look the same in the book.
Note the depressed oval which would make a darker area in the sheet above which might have been printed an engraved image.
Note also the small marks such as slanting lines, propellors & symbols which are probably security marks which could have been changed each batch.
All of the features in the watermarks had to match up to the printing. The paper would of course have shrunk between forming, pressing, drying as waterleaf, sizing and final drying and maturing. The mould maker had to adjust the dimensions to account for this; not easy given variations in fibre, beating and the weather during and after drying. If the blank sheets were printed damp, they would enlarge slightly at that stage.
There are sixteen sets of watermarks on these moulds; a huge amount of careful and precise work.