Frames sizes come in 3 main units of
measurement, namely imperial (feet and inches) metric (centimetres)
& the International Standards Organisation (ISO) system . The
ISO system is sometimes mistaken as a metric system; in fact it is
neither Imperial or Metric but an index of standards.
In the United Kingdom (UK) the most
commonly encountered size is A4. This is the size which is most
often used for documents and certificates. Due to the popularity of
home computers and printers , it has become a common photograph
The dimensions of A4 are 11.69 inches x
8.27 inches in imperial measurement, or 297mm by 210mm in metric.
The key characteristic of an ISO size is it retains its aspect
ratio (shape) when folded or doubled.
An A4 frame means that an A4 size picture
can be framed by dropping the sheet into the insert area without
cutting. Frame sizes by convention refer to the area of picture to
be framed, which means (with the exception of borderless clip
frames) that the actual frame will be larger than the specified
size. The overall visible frame size can be estimated by adding the
frame moulding size less a 1/4" to the frame (insert) size.
Size A4 has good reason to be popular, it
is aesthetically pleasing, provides a useful size for document use,
easily scaled, and gives a near 3 by 2 Aspect ratio for photograph