A process for producing a colorfast thermal appliqué using a polyester knit fabric blank, dye-sublimation printing a graphic image on the fabric blank, and laminating a triple-layer polyurethane adhesive on another side of the printed fabric blank. The triple-layer adhesive comprises a first layer of clear ink resistant polyurethane adhesive followed by a white-pigmented ink resistant polyurethane adhesive and a third clear layer of ink-resistant polyurethane adhesive. The first layer of the triple-layer adhesive is fused under combined temperature and pressure to the polyester blank until said first and second layers impregnates into said fabric blank. The fabric blank is then cut into a discrete finished appliqué that does not substantially change the physical and visual characteristics of a performance fabric substrate to which the appliqué is applied.