Paper was produced in many centres around Europe, in areas where there was plentiful water which was necessary for the procedure of its production. Paper mills were usually built alongside rivers or other available water outlets.
I am providing a link to a very interesting article on some well-known centres of paper production in Italy, showing the way paper is made. (Thanks to Pixartprinting, 2017) :
5 paper museums to visit in Italy this summer | Pixartprinting
Paper did not reach Malta only from Italy. In the first half of the 19th century, Malta was importing paper from different sources. We find printers obtaining their supply of paper from Marseilles, Genova and also from Trieste. More on this in the forthcoming publication.
Printers were importing paper for their own different requirements - for printing daily newspapers, for the printing of books, or for writing documents, for drawing and painting, and also for the writing and printing of music. The quality of the paper would therefore also vary, depending on what it was used for. We find a number of specific references to 'music paper' (carta di musica) which would probably have been used as manuscript paper:
In 1817 music paper was arriving from Catania; In 1838 it reached Malta from Venice; between 1839-1842 it came in regularly from Naples; 1839, 1840 from Marseille; 1841 from Trieste;.....
These are just a few examples. Some music outlets sold 'ruled paper', meaning that it would save people from ruling their stave lines manually, as was often done. In 1887, Eduardo Farina who had a music establishment at 67 Strada Reale, Valletta, specified that he was selling 'ruled music paper' (carta rigata da musica).
For details of the above music paper importations, see Anna Borg Cardona "Malta's Importation and Sale of Musical Instruments and Musical Goods 1800-1900" in A Timeless Gentleman - Festschrift in honour of Maurice Degiorgio (Malta: FPM 2014) 397-409.