Abstract: Method for producing a thermoplastic resin film or sheet useful for chelate color printing which involves contacting at least one surface of a thermoplastic resin film or sheet with a mixed liquid composition comrising (i) a liquid capable of dissolving or swelling said thermoplastic resin, (ii) a liquid having no ability to dissolve or swell said thermoplastic resin, being compatible with said liquid (i) and having a faster rate of evaporation than said liquid (i), and (iii) an inorganic compound containing at least one metal atom selected from the group consisting of iron, vanadium, titanium, molybdenum and tungsten, or an organic compound capable of forming a chelate compound with the metal atom and developing a color, and evaporating off said liquids (i) and (ii), thereby to form a porous surface layer of the film or sheet to which is adhered an uppermost chelate color printing layer comprising said inorganic or organic compound (iii).