This painting by E.L. Kirchner "Akte im Wald" from 1912 had been varnished in the past. Kirchner was a fierce opponent to varnishing and was aiming at a matte surface with luminous and brilliant colour.
The applied coating gave a stark gloss and had yellowed severely.
By removing the coating from the porous paint, the intended appearance could be regained.
This gain in appearence was mirrored at auction, when the restituted painting doubled its estimate. For further information on the paintings history visit:
http://www.van-ham.com/van-ham-restitutionen/sammlung-alfred-hess.html