The modern tendency is to call this subject the 'conservation' of works of art,
although a 'conservator' is, strictly by definition a museum curator.

Conservation includes the actions taken and studies made to revive damaged or
deteriorating works of art and maintain them under correct, monitored
conditions.

Privately owned pictures or objects, which will most likely be brought to a commercial conservation studio, rarely benefit from such care at any other time.

Restoration refers to the removal of surface dirt and discoloured varnish layers,
the replacement of missing portions imitating the original by the sympathetic
use of similar pigments, or building up fragments of sculpted or moulded areas
of an object.

For the general art-aware public the subject is referred to as restoring and
its practitioners 'restorers'. By either name, their aim is to preserve and maintain
the art objects as close to the original state as they can for the benefit of
appreciating the beauty created by the artists for as long as possible
with the aid of experience, skill and scientific knowledge. (see painting structure)

Andromeda and Perseus - Rubens