PAPER SIZES

                                   International paper sizes

The basis of the international series is a rectangle having an area of one square metre (A0), the sides of which are in the proportion of 1:2. This is the proportion of the side and diagonal of any square. All the A series are of this proportion, enabling them to be doubled or halved and remain in the same proportion, which is useful for photographic enlargement i or reduction. AO is twice A1 which is twice A2 and so on. Where larger sizes than AO are needed the A is preceded by a figure, thus 4A is four times A0.

The B series are sizes intermediate between any two A sizes.i This series is used mostly for posters and charts. The C series are envelopes to suit the A sizes.

DL or long sizes are obtained by dividing the A and B series into three, tour or eight equal parts parallel to the shorter side so that the proportion of 1 2 is not maintained. In practice, the long sizes should be produced from the A series only. The dimensions of these series are of the trimmed or finished size.