The forehead is 4 cm square, comparable to official seals and government decrees. How big is 4×4? But there are some, but ordinary people don't use them. If there are private seals of ancient emperors, some are close to 4 cm square, and some are dry dragons. Seals are generally the specifications of seals-there are square seals such as square, rectangular, round and irregular (we often say that they are biased), such as name seals, family seals, house name seals, leisure seals, appreciation seals and collection seals. The 4 cm square seal you mentioned is usually used for large works. In ancient times, there was an unwritten convention for the seal of the collection or the signature of the author, that is, the big seal was sealed and the small seal was sealed. In the picture frame, most ancient female literati used pentagonal seals as the size of their names and home seals.
The size of the five-point print is almost 1.5 cm square.
Male literati generally use six-point seal as the size of their names and home seals. Printing at six o'clock is almost 1.8 cm square.
Most of the house name seals, leisure seals, appreciation seals and appraisal seals are more than 3 cm square; But not necessarily, as I said above, it should be adjusted according to the frame size. Anyway, these are ancient usage habits, which are widely used now and are not so strict. However, the common name stamp for men is 1.8 cm square, which is more appropriate. Please ask questions if you don't understand ~