DIN A paper sizes (√2 series)
Formato de papel DIN A (serie √2)
- Date
- 1922 · confidence high
- Place
- Berlin, Germany
- Credited to
- Walter Porstmann and DIN
- Field
- Knowledge & symbols
What it is
A series of sheets whose side ratio is √2, so that folding in half keeps the shape. A4 is the office format for most of the world.
Georg Christoph Lichtenberg already noted the √2 property in 1786; the DIN 476 standard was published in 1922.
What it led to
- the ISO 216 standard (1975)
- exact enlargement and reduction on photocopiers
- standardised envelopes, filing cabinets and folders