A marking system includes a composition having at least one color precursor, a moldable substrate having a color developer, and a marking instrument for applying the composition to the moldable substrate to form at least one mark on the moldable substrate. A method of producing a colored three-dimensional molded object includes the steps of manipulating a moldable substrate having a color developer into a molded shape having an outer surface; and applying, on the outer surface of the molded shape, a first composition having at least one color precursor to a first portion of the molded shape.