The Alkaline Advantage
Many manuscripts from the Islamic Golden Age, written on Samarkand paper, survive in excellent condition after more than a millennium. Modern paper made after the mid-19th century often yellows and becomes brittle in just 50 years. The chemical difference is a matter of pH. Most modern paper was produced using an alum-rosin sizing, which creates acidic conditions. In the presence of moisture, acid breaks down the long cellulose chains that give paper its strength, a process called acid hydrolysis. This reaction is self-catalyzing; as the cellulose degrades, it produces more acids, accelerating its own destruction.
Samarkand paper, however, is alkaline. While the exact historical recipes varied, the process resulted in a paper with a natural alkaline buffer, likely due to the local water and processing techniques. This alkaline reserve, which functions similarly to the calcium carbonate (CaCO₃) added to modern archival paper, neutralizes acids. It counteracts both acids absorbed from atmospheric pollutants like sulfur dioxide and those generated naturally by the aging of cellulose itself. By preventing acid hydrolysis, the paper's long cellulose fibers remain intact, preserving the paper's strength and flexibility for centuries.
From Mulberry Bark to Polished Page
The history of Samarkand paper begins with the inner bark of young mulberry branches (Morus alba). This material was chosen over cotton or hemp because its long, pest-resistant cellulose fibers produce a durable, flexible sheet. The production technology arrived in the region around the 8th century, famously after the Battle of Talas in 751 AD when Chinese papermakers were reportedly captured. Samarkand artisans refined the process, creating a product famous throughout the medieval world.
The manufacturing process is entirely manual. Workers strip the mulberry bark, boil it for hours to soften it into a pulp, and then pound it into a uniform, dough-like consistency using large, water-powered wooden hammers. This pulp is mixed with water and then strained through a screen to form a sheet. After pressing and drying, the paper has a slightly rough surface. The final, important step is burnishing. Each sheet is polished on a flat stone with a seashell or piece of agate. This creates an exceptionally smooth, non-porous surface that was ideal for calligraphy, preventing ink from bleeding. The finished, unbleached paper has a characteristic pale ochre or yellowish tint.