A 18th C. watercolour with an optical illusion.
Ref.:
22237
An optical watercolour. Size: 23 x 28 cm. The watercolour of a girl playing a harp is punctured in such a manner that when a light is put behind it, an optical illusion follows. The watercolour still retains its original goldleaf covered frame and glass. A very rare item. Holland, second half 18th c.