From DT Online
Decoupage is a method of applying a surface decoration to an object by cutting out coloured shapes and pictures (usually from paper) and sticking them on to otherwise plain objects.
Features and Uses
The technique was used in China to decorate items as early as the 12th century. It became popular in Italy during the 17th century and from there the practice spread throughout Europe and was much used by the Victorians (in Jane Austen's Pride & Prejudice, Mr Bingley refers to 'covering screens' as one of the pursuits of 'a truly accomplished young lady'). Developments in printing technology led to the production of pre-cut pictures and shapes (later known as 'scraps') for decorating furniture. Decoupage Papers are available today from craft shops and suppliers.
The pieces of paper can be stuck on to the surface with a suitable Adhesive such as PVA and once covered, the object is then given several coats of varnish or laquer to produce a shiny durable finish.
Note: Thinned coats of PVA could be used to simulate varnishing.