An isolation coat is a clear, non-removable coating that serves to physically separate the paint surface from the removable varnish.
The isolation coat serves two purposes:
1) To protect the painting if/or when the varnish is removed by separating the pigmented area of the painting from the solvents used in removal.
2) To seal any absorbent areas in order to create an even surface on which to apply the varnish.
