Traditional Paper Sizes
In Europe everyone from a school child to your granny knows that you buy A4 paper for your printer at home. It measures 297 x 210 mm every time you buy it because it's a standardised size whether or not you buy it in the UK, Germany or Portugal. Some people know that A5 is half the size of A4 and often used by card makers and A3 (twice the size of A4) is a popular photographic printing size. Professional printers use B size paper. These are slightly larger than A sizes which allows for the paper to be trimmed down to an A size after it's been printed. However ordering paper in the old days wasn't quite so simple......