This International Standard specifies a method for determining the dimensional change of photographic films and papers caused by: — variations in equilibrium moisture content due to change in the relative humidity (RH) of the atmosphere (humidity coefficient of expansion); — change in temperature (thermal coefficient of expansion); — processing; — ageing. This International Standard deals with the moisture content and thermal history of the specimens before measurement, the atmospheric conditions during measurement, and the treatment of the data. It does not describe the various experimental techniques used to make the measurements. This International Standard is not suitable for determining the dimensional change of instant photographic film.