History of paper sizes

History of paper sizes:

Ever wondered why A4 size is called A4 or what is the history behind “legal size” of paper or what is the relation between A4 and A3?

A4 paper is the standard paper size used worldwide except US, Canada, and Mexico. The key feature of A Series paper size is that A4 (21cm x 29.7cm or 8.25” x 11.67”) is half the size of A3. A3 is half the size of A2. A2 is half the size of A1 and A1 is half the size of A0. A0, the largest in the range at 84.1cm x 118.9cm is exactly 1m2 of paper. The aspect ratio (Height : Width) remains the same in all sizes of A series which is 1 : 1.4142 (Lichtenberg Ratio). It goes from A0 to A10. There are other series like B series, C series based on this same principle but having different paper sizes. US uses paper sizes of “letter” 8.5 inch x 11 inch (about 21.5 cm x 27.9 cm), “executive”, “legal” etc.

In Bologna, Italy, in the year 1398, a marble tablet inscribed with the outlines of four sizes of paper [small, medium, large, and extra-large] was placed in a public place to serve as a guide for the sizes of paper manufactured in that region of Italy. Centuries later, in 1786, physics professor Georg Christoph Lichtenberg of Germany noted that in a paper having a height-to-width ratio of the square root of two (1:1.4142), the aspect ratio was still same, i.e. 1:1.4142, when paper was cut into two. This helped in reducing the wastage while cutting the paper.

Paper official metric standard is based on a German standard originally from 1922 DIN (Deutsche Institut für Normung) standard no. 476. In 1975, A series sizes became an ISO Standard 216 and the official United Nations document format. It was proposed for an early draft of ISO 216 to recommended the special size 210 × 280 mm (a format sometimes called PA4) as an interim measure for countries that use 215 × 280 mm paper and have not yet adopted the ISO A series. Incidentally, this PA4 format has a width/height ratio of 3:4, the same as traditional TV screens and most computer monitors and video modes.

Letter size: As far as can be determined, the 8½ x 11" letter size began to be used in the United States during or shortly after the First World War. The historic origins of the U.S. letter size format are relatively obscure. In 1921 a different 8 x 10½" format was established as the standard for U.S. Government letterheads, and continued until the Reagan administration declared in 1980 that the official paper format for the U.S. government would be the 8½ x 11" size.

Legal Size: According to one story, during the time of Henry VIII (King of England: 1509-1547), paper was printed in 17″ x 22” sheets because this was the largest size of mold that papermakers could carry. These large sheets were known as foolscap. Legend has it that lawyers would simply cut the foolscap in half and use the sheets for official documents. Lawyers liked longer paper so that they could take more notes than would fit on a normal page. In 1920s/1930s at the same time that the standard of 8 x 10½" paper was adopted in US, another committee known as the Committee on the Simplification of Paper Sizes recommended six completely different paper sizes. These sizes appear to have been selected merely because of their being traditional. Our legal size paper (8½ x 14" / 17 x 28") is also one of the papers specified by the Committee on the Simplification of Paper Sizes.