Xerography or electrophotography is a dry photocopying technique. Its fundamental principle was invented by Hungarian physicist PÃ¡l SelÃ©nyi and based on SelÃ©nyi's publications Chester Carlson applied for and was awarded U.S. Patent 2,297,691 on October 6, 1942. The technique was originally called electrophotography.
A retrospective, generally, is a look back at events that took place, or works that were produced, in the past. As a noun, retrospective has specific meanings in medicine, software development, popular culture and the arts. It is applied as an adjective, synonymous with the term retroactive, to laws, standards, and awards.
1590s, a gathering together again, from French rÃ©collection (14c.) or directly from Medieval Latin recollectionem (nominative recollectio), noun of action from past participle stem of recolligere (see recollect). Meaning act of recalling to memory is from 1680s; a thing or scene so recalled, from 1781.