The present invention concerns a thermal imaging process using (i) a donor element comprising on a support a donor layer comprising a binder and a thermally transferable reducing agent capable of reducing a silver source to metallic silver upon heating and an oxidised form of the reducing agent being colored or being capable of forming a color and (ii) a receiving element comprising on a support a receiving layer comprising a silver source capable of being reduced by means of heat in the presence of a reducing agent and comprising the steps of:bringing said donor layer of the donor element in face-to-face relationship with the receiving layer of the receiving element,image-wise heating a thus obtained assemblage to cause image-wise transfer of the thermally transferable reducing agent from the donor layer to the receiving layer in accordance with the amount of heat applied andseparating the donor element from the receiving element.