Silver behenate is used in thermographic materials as the image silver reservoir. To obtain an imaging material with optimal sensitometric and physical properties, it is important to obtain fundamental insight into and basic knowledge of silver behenate. A method for determining the relative crystallinity has been developed based on powder x-ray diffraction (XRD). In addition, the thermal behavior of silver behenate crystals has been studied using XRD. The image silver crystal size, silver behenate crystallinity and phase transitions were determined at different temperatures.