Copying

Copying is the duplication of information or an artifact based only on an instance of that information or artifact, and not using the process that originally generated it. With analog forms of information, copying is only possible to a limited degree of accuracy, which depends on the quality of the equipment used and the skill of the operator. There is some inevitable deterioration and accumulation of "noise" (random small changes, not sound) from original to copy; when successive generations of copy are made, this deterioration accumulates with each generation. With digital forms of information, copying is perfect. Copy and paste is frequently used for information a computer user selects and copies to an area he or she wishes.

Most high-accuracy copying techniques use the principle that there will be only one type of possible interpretation for each reading of data, and only one possible way to write an interpretation of data.

In art

In visual art, copying the works of the masters is a standard way that students learn to paint and sculpt. In sculpture, copies have often been made using devices such as the pointing machine, the pantograph or, more recently, computer guided router systems that scan a model and can produce it in a variety of materials and in any desired size. Another way of copying three-dimensional works is by lost-wax casting and other forms of molding and casting.