The paper deals with a statistical study on the thermal degradation of some old paper supports. The experimental data permit establishment of some regression models, which describe the dependence between the half time and the temperature at which the paper support is kept and, respectively, between the exposure time of the paper supports to a certain temperature and the absorbency value of a characteristic peak, representative for the paper support. (C) 2008 Elsevier B.V. All rights reserved.