Removing the varnish
with solvents. Before doing so, the
restorer must determine the safest and
most efficient solvent for the removal
of the particular varnish.
The discolored varnish has been removed from the left half of The Virgin and Child, revealing cooler, brighter colors. Some cleaning tests are still visible in the remaining yellowed varnish, for example on Mary's temple and the child's belly.
The varnish layers of most older paintings have been removed and reapplied several times. Before the introduction of modern materials, varnishes had to be taken off with harsh cleaning solutions. In the process, however, these solvents often attacked the medium of the paint itself. Glazes, the thin layers of medium-rich paint on the painting's surface, are especially vulnerable to solvents.
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