Pictures can be worn and damaged and also fade, rot or even corrode. Change and decay cannot be prevented altogether, but by their understanding of the materials involved, a restorer can assist in preserving the painting and frame. In fact, a picture begins to deteriorate from the moment it is finished. Changes are produced by chance, by light and air, dust, wear, harmful gases and dampness.
So, conservation should be viewed as an ongoing matter, not just a case of magical restoration after serious damage has occurred in the hope of returning to the full original aspect of the picture.
The most that a restorer can do is stave off the working of those factors that would affect the picture and to recover what is left of its 'character'
The conservators aim should be to responsibly and sympathetically preserve the character of the original as much as possible.
'....the basic concept of cleaning must not be the recovery of a presumed original aspect of the colour, but a reconstruction in an analogous and proportional manner of the correct relationships between colours and tones. Thus recovering the legibility of the work of art while respecting both the aesthetic and historic characteristics of its life”.