Papers

Paper refers to sheets of material made primarily from cellulose fibers that are processed into thin, flat sheets for writing, printing, packaging and other uses. Most modern paper is made from wood pulp or recycled fibers; production involves pulping, refining, forming, pressing, drying and often coating. Standard sizes vary by region; ISO A-series is common internationally, with A4 at 210 by 297 mm, while North America uses Letter and Legal.

Papers vary in composition and properties. Writing and printing papers are distinguished by fiber type, grammage (mass per unit area), brightness, opacity and surface texture. Cardboard and corrugated board use thicker grades; tissue papers are softer and more absorbent; coatings can improve ink receptivity. Paper is widely recyclable; sustainable production emphasizes responsible sourcing, recycled content and reducing chlorine-based bleaching; certification schemes exist (FSC, PEFC).

Uses and formats. Beyond writing and printing, paper is used for packaging, newspapers, tissue products and specialty papers such as tracing or archival paper. Archival-quality papers avoid acidic contents and retain strength over time, important for records and art.

Academic papers. In scholarly contexts, a paper is a written report of original research or a literature review, typically structured with abstract, introduction, methods, results, discussion and references. They are commonly peer-reviewed and indexed in bibliographic databases; many appear in journals, conference proceedings or preprint servers; citation practices vary by discipline.

History and significance. Paper originated in China around the 2nd century CE and spread to the Islamic world and Europe. The development of mechanical papermaking and industrial pulp mills in the 18th–19th centuries enabled mass production, shaping education, administration and culture.