A coated glass mat is formed by applying a coating mixture to a surface of a glass mat substrate, and then by drying the coated glass mat. As a result of the coating composition, the resultant mat attains a predetermined target spectral characteristic, e.g., a desired or target color. The coating mixture is formed by mixing together a mineral pigment filler, a solvent, a binder (e.g., organic latex binder), (optionally) a dispersing agent, and (optionally) a colorant. The type and amount of the mineral pigment filler is judiciously chosen to impart the predetermined spectral characteristic to the coated glass mat upon drying. In fact, although the coating mixture may include a separate, optional colorant, the mineral pigment filler is chosen as a primary color determinate for the completed coated glass mat. The primary determinative influence of the mineral pigment filler on the spectral characteristic of the coated glass mat is evident by the relative amounts of the mineral pigment filler and the colorant. In particular, a maximum ratio of "as received weight" of colorant to "dry weight" of filler is less than about 0.003; a ratio of "dry weight" of colorant to "dry weight" of the coating mixture does not exceed 0.4%. Advantageously, use of the inexpensive mineral pigment filler as the primary color determinate for the completed coated glass mat obviates the need is for larger amounts of more expensive colorant, thereby providing economy as well as efficiency in production.