The periodic illumination of a solid sample results in cyclic heating and cooling which in turn produces an acoustic signal at the same frequency as the illumination rate. The strength of this signal is dependent on the light source, the absorption spectrum of the material, and the optical and thermal properties of the surface layers. The variation in the strength of the photoacoustic signal as the illumination rate is changed can provide information on the number and color of any surface layers present. The variation in acoustic signal, observed as various points on the sample surface are illuminated, can provide a sensitive detector of changes in surface condition or composition. This method has been applied to selected East Cretan white-on-dark ware sherds, and the results of the examination of outer decorated surfaces as well as inner surfaces are reported. See also AATA 20-771.