When A.P.D.R. appears on an antique print, it means it was engraved “avec privilège du roi” – or licensed by the king.  This is an annotation which one sees only on prints published before the French revolution. It was used to indicate that the print had been approved by the French censures.

Perspective View

Perspective Views (Also: Optical print, vue perspective, vue d’optique or in German, Guckkastenblättern) were meant to be seen with a special viewer or Zograscope to enhance the three dimensional effect. They were very popular in the 18th and 19th centuries.