on Bond paper –

• Bond paper is a high quality durable writing paper similar to bank paper but having a weight greater than 50 g/m2. The most common weights are 60 g/m2 (16 lb), 75 g/m2 (20 lb) and 90 g/m2 (24 lb). The name comes from its having originally been made for documents such as government bonds.

or what is known as parchment

• Parchment is a writing material made from specially prepared untanned skins of animals—primarily sheep, calves, and goats. It has been used as a writing medium for over two millennia. Vellum is a finer quality parchment made from the skins of young animals such as lambs and young calves.