8. The size of the front seat for paper opening is 270mm × 390mm, finished product size is 260mm × 370mm。 8-folio paper is not A4 paper. 8-folio paper is larger than A4 paper. The size of A4 paper is 210mm × 297mm。 Whether it is positive size or large size, the size of 8-folio paper is slightly larger than that of A4 paper.

A4 paper is to fold the paper of type a basic size four times, so the area of a piece of A4 paper is one fourth of the area of the basic paper, that is, 1 / 16.

K-type paper is often referred to as open type paper. The classification of K-type paper is to divide a large 1K paper into two pieces into 2K, half of 2K paper into 4K, half of 4K into 8K, half of 8K into 16K, half of 16K into 32K, etc.

The folio is based on the whole sheet of paper. The number of small sheets cut and folded for each full sheet of paper is called the folio. In China, it is customary to name the folio based on the geometric level. The size of the whole paper after folding in half is folio, then folded in half is 4 folio, then folded in half is 8 folio, then folded in half is 16 folio, then folded in half is 32 folio, then folded in half is 64 folio, and so on.