A thermal transfer donor element has a polymeric support having at least a portion thereof coated with a thermal transferable protective transparent film. This film comprises: (1) a poly(vinyl acetal) in an amount of at least 50-70 weight %, (2) a second polymer, and (3) colloidal silica. In addition, (a) the molecular weight of the second polymer is greater than the molecular weight of the poly(vinyl acetal), (b) the weight ratio of the poly(vinyl acetal) to the second polymer is at least 5:1 and up to and including 12:1, (c) the weight ratio of colloidal silica to the second polymer is at least 1.5:1 and up to and including 3:1, and (d) the amount of colloidal silica is at least 10 weight % and up to and including 20 weight %, based on total thermal transferable protective transparent film dry weight.