Restoration: The repair or renovation of artwork that has already sustained decay. It is the attempt to restore a work to its original, undamaged appearance and concerns the aesthetic part of artwork.

Focus of restoration: The restoration of artwork focuses on rehabilitating the intent of the original artist to the viewer. It involves restoring a piece back to its original, authentic appearance or function. 

The purpose of restoration: To preserve the integrity and, thus, the value of an authentic artwork. Restoration treatments completely respect authenticity and the originality of the artist.