Shown above are two boxes of Duke-sized (5½"x7") writing paper in slightly different shades of pale blue. I acquired them together in a single ebay purchase. The Silverbrook Superfine paper is a shade often called ‘azure’ (in relation to stationery), with the Hollingworth Rag Bond a slightly deeper tint. The latter is watermarked, the former not.
‘Silverbrook’ was a brand-name once associated with F. Keay & Co. of Birmingham, about whom I know practically nothing. Nor do I know what ‘superfine’ might have meant to the erstwhile paper-buyer–if anything–beyond some vague expectation of higher quality. Many paper-makers listed ‘fine’ and ‘superfine’ papers among their product-lines (and even ‘extra superfine’ wasn’t unheard of). If those terms had any more meaningful definition, I’m unaware of it.
Hollingworth on the other hand had a long-held reputation for first-rate products. Rag-based papers were typically higher-end, expensive ones. Jenners Ltd. of Princes St., Edinburgh (whose name is printed on the box), was for well over a century that city’s principal department store. Hollingworth also made paper for Harrods. ‘Bank’, ‘Bond’ and ‘Loan’ were terms for paper weights: Banks were thin and light; Loans were thicker, heavier and more durable; Bonds were of normal medium weight, akin to modern office/copier paper.
Neither box of paper came with any matching envelopes. Fortunately, Duke-sized envelopes in blue haven’t been too hard to find on ebay.