papersizing

Paper sizing refers to two related concepts: sizing as a treatment applied to paper to alter its interaction with liquids, and paper size as the standardized dimensions of sheets used for printing and writing.

Sizing (the treatment) is applied to control absorbency and ink spread. It can be added to the pulp during papermaking (internal sizing) or applied to the finished sheet (surface sizing). The aim is to improve writing and printing quality, increase water resistance, and influence surface feel. Traditional sizing used substances such as rosin with alum or gelatin and starch. Modern formulations often rely on synthetic agents like alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA). The chosen sizing affects ink holdout, brightness, strength, and aging characteristics.

Paper sizes are standardized sheet dimensions used internationally to ensure compatibility in printing, publishing, and mailing. The ISO 216 standard defines the A-series, including A0, A1, A2, A3, A4, and so on, where each size has the same aspect ratio and can be obtained by halving the area of the next larger size. The A-series is widely used for documents and consumer printing. The B-series provides larger sizes used in publishing and posters, while the C-series specifies envelope sizes that fit the A-series sheets. The DIN/ISO system originated in Europe (DIN 476) and was formalized as ISO 216 in 1975. In North America, common sizes include Letter (8.5 by 11 inches), Legal (8.5 by 14), and Tabloid (11 by 17).

Practical implications include layout and folding strategies, print production planning, and cross-region compatibility. Together, paper sizing and standardized sheet sizes influence the design, handling, and distribution of printed materials.