Dielectric analysis using the open-ended coaxial probe technique was applied to the non-invasive monitoring of moisture sorption and desorption processes in three different samples. Results are reported for the humidification and dehumidification studies in naturally aged unprimed canvas containing remnants of aged lining adhesive, the response of artificially aged primed canvas sample to atmospheres of relative humidities corresponding to 60, 80 and 95%, and the effect of temperature variation on moisture sorption processes in a sample of naturally aged primed canvas from Landseer's Study of a Lion.