It appears to be regarded as a traditional size for paper for drawings and for some frames. Rather than A3, which is a similar size, yet not so long a time a specified size.
Yet it appears to be a French size.
The name Cloche (Bell in English) being because at one time (some of?) the paper of that size had a watermark of a bell.
https://papersdb.com/french/cloche
Yet the metre as a unit of measurement is not that old in terms of art traditions.
I am wondering why this size is used in England.
William
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