A thermal imaging process is provided using (i) a donor element comprising on a support a donor layer comprising a binder, a thermotransferable reducing agent capable of reducing a silver source to metallic silver upon heating and a thermotransferable toning agent and (ii) a receiving element comprising on a support a receiving layer comprising a silver source capable of being reduced to metallic silver by means of heat in the presence of a reducing agent, said thermal imaging process comprising the steps ofbringing said donor layer of said donor element into face to face relationship with said receiving layer of said receiving element,image-wise heating a thus obtained assemblage preferably by means of a thermal head, thereby causing image-wise transfer of an amount of said thermotransferable reducing agent to said receiving element in accordance with the amount of heat supplied andseparating said donor element from said receiving element.Images having a neutral grey tone can be obtained according to this method. The present invention further provides a donor element for use in the above method.