A thermal dye transfer assemblage comprising:(I) a dye-donor element comprising a support having thereon a dye layer comprising a dye dispersed in a polymeric binder, the dye being a deprotonated cationic dye which is capable of being reprotonated to a cationic dye having a N--H group which is part of a conjugated system, and(II) a dye-receiving element comprising a support having thereon a polymeric dye image-receiving layer, the dye-receiving element being in a superposed relationship with the dye-donor element so that the dye layer is in contact with the polymeric dye image-receiving layer, the polymeric dye image-receiving layer comprising a mixture ofa) a polymer having a Tg of less than about 19.degree. C. and having no or only slight acidity; andb) an acidic material containing at least 0.0007 meq/m.sup.2 of acid; the a) and/or b) having incorporated therein a plasticizer containing:(i) at least the following groups in the order given:E--Q--X--A wherein Q is a carbonyl or sulfonyl;X is N or O;E is an aromatic ring; andA is an alkyl or oxyalky group having up to 5 consecutive carbon atoms; or(ii) a phosphate group having at least one aromatic ring attached thereto;said plasticizer being present in an amount of up to about 25 weight percent of the polymer.