Other historical systems, such as the British Foolscap and Imperial sizes, have largely been phased out in favour of ISO or ANSI standards.
ISO paper sizes are all based on a single aspect ratio of the square root of 2, or approximately 1:1.41421.
Briefly after the introduction of the metric system, a handful of new paper formats equivalent to modern ones were developed in France, having been proposed by the mathematician Lazare Carnot, and published for judicial purposes in 1798 during the French Revolution:[4] These were never widely adopted, however.
Early in the 20th century, the ratio was used to specify the world format starting with 1 cm (0.39 in) as the short edge of the smallest size.
In Mexico, Costa Rica, Colombia, Venezuela, Chile, and the Philippines, the US letter format is still in common use, despite their official adoption of the ISO standard.
[need quotation to verify] The C series is defined in ISO 269, which was withdrawn in 2009 without a replacement, but is still specified in several national standards.
variables are the distinct first terms in the three geometric progressions of the same common ratio equal to the square root of two.
The former has been withdrawn in 2002 in favour of adopting the international standard as DIN EN ISO 216, but part 2 has been retained and was last updated in 2008.
Six years later, it was replaced by OST 5115 which generally followed DIN 476 principles, but used Cyrillic lowercase letters instead of Latin uppercase, had the second row shifted so that б0 (B0) roughly corresponded to B1 and, more importantly, had slightly different sizes:[14] The general adaptation of ISO 216 in the Soviet Union, which replaced OST 5115, was GOST 9327.
A standard for technical drawings from 1960, GOST 3450,[15] introduces alternative numeric format designations to deal with very high or very wide sheets.
Designations for pre-printed drawing paper include the base sizes and a suffix, either T for trimmed or U for untrimmed sheets.
As a compromise between the two most popular paper sizes globally, PA4 is used today by many international magazines, because it can be printed easily on equipment designed for either A4 or US Letter.
The Weltformat ('world format') was developed by German chemist Wilhelm Ostwald in 1911 as part of Die Brücke, around the same time DIN 476 was first discussed.
It shares the same design primitives, especially the aspect ratio, but is based upon 1 cm as the short edge of the smallest size.
In East Asia – Japan, Taiwan, and China in particular – there are a number of similar paper sizes in common use for book-making and other purposes.
A single designation is often used with slightly different edge measurements: the base sheet is labelled 1K (or 1开, where K standards for Chinese: 开本; pinyin: kāiběn; lit.
Letter, Legal and Ledger/Tabloid are by far the most commonly used of these for everyday activities, and the only ones included in Cascading Style Sheets (CSS).
The American Forest and Paper Association argues that the dimension originates from the days of manual papermaking and that the 11-inch length of the page is about a quarter of "the average maximum stretch of an experienced vatman's arms.
[24] US paper sizes are currently standard in the United States and are the most commonly used formats at least in the Philippines, most of Mesoamerica[30] and Chile.
Mexico and Colombia, for instance, have adopted the ISO standard, but the US Letter format is still the system in use throughout the country.
Ronald Reagan therefore had the US government switch to regular Letter size, which is half an inch both longer and wider.
[27] The former government size is still commonly used in spiral-bound notebooks, for children's writing and the like, a result of trimming from the current Letter dimensions.
In 1996, the American National Standards Institute adopted ANSI/ASME Y14.1 which defined a regular series of paper sizes based upon the de facto standard 8+1⁄2 in × 11 in (216 mm × 279 mm) Letter size which it assigned "ANSI A", intended for technical drawings, hence sometimes labeled "Engineering".
Unlike the ISO standard, however, the arbitrary base sides forces this series to have two alternating aspect ratios.
[33] With care, documents can be prepared so that the text and images fit on either ANSI or their equivalent ISO sheets at a 1:1 reproduction scale.
Some visual arts fields also continue to use these paper formats for large-scale printouts, such as for displaying digitally painted character renderings at life-size as references for makeup artists and costume designers or to provide an immersive landscape reference.
In addition to the system as listed above, there is a corresponding series of paper sizes used for architectural purposes defined in the same standard, ANSI/ASME Y14.1, which is usually abbreviated "Arch".
[35] "Demitab", "broadsheet" or "tabloid" format newspapers are not necessarily printed on paper measuring exactly their nominal size.
[42] The standard British imperial uncut paper sizes used in offices and schools were "foolscap", "post", and "copy".
In a recent trend,[63] many newspapers have been undergoing what is known as "web cut down", in which the publication is redesigned to print using a narrower (and less expensive) roll of paper.