簽字 qiānzì = to sign (a signature).
印鑒 yìnjiàn = seal impression / stamp / mark from a seal serving as signature.
名章 míng zhāng = name seal.
Name Seals represent the artist’s name(s) (family and/or given) and style names. Each Chinese calligrapher, painter, or poet can have more than one style names. The name seals are stamped below the poem and signature in a painting or calligraphy work. If there are two or more name seals in a work, a balance of Ying and Yang needs to be considered; the sizes of the seals need to be similar; the distance between seals need to be at least the size of one of the seals stamped. Name Seals can also be used as “Hand Seals.” Name Seals are usually square in shape because they have more serious meaning for art.
閑章 xiánzhāng = recreative seal, bearing not the owner’s name but a well-known verse or such, and used for artistic purposes on paintings etc.
Mood Seals enriches the whole view of a work. It can be decorative and bring balance to the whole work. The contents of mood seals are mostly related to the artist’s taste, preference, the main content of the work in regarding to phrases or images, the time, year, and mood when the work is created, the implied meaning of the work, and etc.
Mood Seals can be further categorized into the following types according to the locations where they are stamped on a work:
1. 引首章 (Leading Seals).
The Leading Seals are usually placed at the top right corner of a work. It can be coordinated with the Signature and Name Seals. It will also bring “wholeness” to the painting. They have shapes like rectangle, oval, and etc. that look more natural.
2. 壓角章 (Corner Seals).
The Corner Seals are usually stamped on the corner near the bottom of the work. They can lower the weight percentage of the whole work for balance. Their shapes are mainly square or rectangle.
3. 腰章 (Connecting Seals, literally Waist Seals).
The Connecting Seals are usually stamped near the middle of the work or between different sections of the work. A longer or larger work somewhat looks disconnected from the start to the end. If the Connecting Seal(s) can be used properly, they can make the whole work more connected. They are mainly in the shape of rectangular bar or in any other shapes.
Other seals are:
收藏章 (Collector’s Seals).
The Collector’s Seals are for private collections of books and artworks. They can be in any shape like rectangle, round, and etc.
手章 (Hand Seals).
The Hand Seals are stamped after the signatures for documents and contracts. The calligraphy on the Hand Seals are usually more standardized.
The signatures and seal stamps on Chinese painting and calligraphy works follow strict norms and traditions. If they are violated, a work will be mocked or demeaned because it is considered ignorant and impolite.
Seal-cutting is traditionally listed along with painting, calligraphy and poetry as one of the “four arts” expected of the accomplished scholar and a unique part of the Chinese cultural heritage. A seal stamp in red is not only the signature on a work of calligraphy or painting but an indispensable touch to liven it up.
The art dates back about 3,700 years to the Yin Dynasty and has its origin in the cutting of oracle inscriptions on tortoise shells. It flourished in the Qin Dynasty of 22 centuries ago, when people engraved their names on utensils and documents (of bamboo and wood) to show ownership or authorship. Out of this grew the cutting of personal names on small blocks of horn, jade or wood, namely the seals as we know them today.
As in other countries, seals may be used by official departments as well as private individuals. From as early as the Warring States Period (475- 221 B.C.) an official seal would be bestowed as token of authorization by the head of a state to a subject whom he appointed to a high office. The seal, in other words, stood for the office and corresponding power. Private seals are likewise used to stamp personal names on various papers for purposes of authentication or as tokens of good faith.
Seals reflect the development of written Chinese. The earliest ones, those of the Qin and Han dynasties, bear the zhuan or curly script, which explains why the art of seal-cutting is still called zhuanke and also why the zhuan script is also known in English as “seal characters”. As time went on, the other script styles appeared one after another on Chinese seals, which may now be cut in any style except the cursive at the option of the artist.
Characters on seals may be cut in relief or in intaglio. The materials for seals vary with different types of owners. Average persons normally have wood, stone or horn seals, whereas noted public figures would probably prefer seals made of red stained Changhua stone, jade, agate, crystal, ivory and other more valuable materials. Monarchs in the old days used gold or the most precious stones to make their imperial or royal seals. Today Chinese government offices at lower levels wood ones.
Seals cut as works of art should excel in three aspects– calligraphy, composition and the graver’s handwork. The artist must be good at writing various styles of the Chinese script. He should know how to arrange within a limited space a number of characters– some compact with many strokes and others sketchy with very few– to achieve a vigorous or graceful effect. He should also be familiar with the various materials– stone, brass or ivory– so that he may apply the cutting knife with the right exertion, technique and even rhythm. For the initiated to watch a master engraver at work is like seeing a delightful stage performance.
Text taken from: http://www.chinavista.com/experience/seal/seals.html