DIN A4: Die Geschichte des Papierformats | ARTE Family

Understanding the A4 Paper Format

Introduction to DIN A4 Format

• The discussion begins with a simple sheet of paper, specifically the DIN A4 format, which measures 21 cm in width and 29.7 cm in height.

• The unique aspect of this format is its proportionality; folding the rectangle in half yields two smaller rectangles that maintain the same height-to-width ratio.

Mathematical Properties

• This proportionality aids in producing various formats (A0, A1, A2, etc.) through successive folding or cutting, minimizing paper waste and optimizing storage.

• There exists a mathematical formula for calculating the aspect ratio of this rectangle: if h is height and l is width, then h/l must equal √2.

Historical Context

• The history of this paper format has German-French roots; Georg Christoph Lichtenberg first noted its properties in a letter dated October 25, 1786.

• Following the French Revolution, efforts were made to standardize paper sizes for taxation purposes. Jean-Baptiste Moise Joliv advocated for specific ratios before the National Assembly on August 21, 1792.

Legislative Developments

• Despite initial attempts at standardization under Louis XIV being unsuccessful due to bureaucratic misunderstandings, legislation was eventually passed on November 3, 1798.

• This law established various formats corresponding to different sizes (e.g., grand registre as A2), but these standards were not widely adopted initially.

Reestablishment of Standards

• In Germany during the late 19th century and early 20th century, chemist Wilhelm Ostwald and engineer Walter Porstmann revived discussions about standardizing paper formats.

• Their efforts culminated in the adoption of DIN 476 in 1922 defining A0 size as a rectangle with an area of one square meter. This standard has since been globally recognized and became ISO 216 by 1975.