Seal (emblem)

A seal is a device for making an impression in wax, clay, paper, or some other medium, including an embossment on paper, and is also the impression thus made. The original purpose was to authenticate a document, a wrapper for one such as a modern envelope, or the cover of a container or package holding valuables or other objects.

The seal-making device is also referred to as the seal matrix or die; the imprint it creates as the seal impression (or, more rarely, the sealing). If the impression is made purely as a relief resulting from the greater pressure on the paper where the high parts of the matrix touch, the seal is known as a dry seal; in other cases ink or another liquid or liquefied medium is used, in another color than the paper.

In most traditional forms of dry seal the design on the seal matrix is in intaglio (cut below the flat surface) and therefore the design on the impressions made is in relief (raised above the surface). The design on the impression will reverse (be a mirror-image of) that of the matrix, which is especially important when script is included in the design, as it very often is. This will not be the case if paper is embossed from behind, where the matrix and impression read the same way, and both matrix and impression are in relief. However engraved gems were often carved in relief, called cameo in this context, giving a "counter-relief" or intaglio impression when used as seals. The process is essentially that of a mould.