The use of the confocal microscope for measurement of the thickness of thin
transparent coatings, such as the varnish layer on compact discs, is descr
ibed. The relationship between true and apparent thickness varies in a non-
linear fashion, but intensity profiles show a good correspondence with calc
ulated profiles. This provides the basis of a nomogram for prediction of co
ating thickness. (C) 2001 Published by Elsevier Science Ltd.