The specification of paper refers to that after the paper is made, it is trimmed and cut into a certain size. In the past, the size of paper was expressed by the number of "openings". At present, China has adopted international standards, stipulating that A0, A 1, A2, B 1, B2 ... and other marks are used to express paper format specifications. According to the standard, the proportional relationship between the width (represented by X) and the length (represented by Y) of paper is X: Y =1:N. ..

According to the size, folio is usually divided into three types: large format, medium format and small format. Taking 787× 1092 paper as an example, 12 format is large format, 16 ~ 36 format is medium format and 40 format is small format. Except for 6 format, 12 format, 20 format, 24 format and 40 format, all other formats are almost square.

Extended data:

Common format size:

1, 8 format: 374×262mm, small 8 format: 368×260mm；; ;

2. Large 16 format: 262× 187mm, small 16 format: 260×184 mm;

3. Big 32 format: 203× 140mm, small 32 format:184×130mm;

4. Big 64 format:131×101mm or 130×99mm,

5. Small 64 format: 127×95mm or 125×92mm.

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