The invention relates in one aspect to a post-formulation concentrated nanocomposite dispersion containing an invisible marker dye. The dispersion typically includes a silicate filler and a matrix polymer dispersed in an aqueous medium as well. The dispersions form optically transparent barrier films wherein the dye is effective to indicate film thickness on a substrate. Specific embodiments of this invention include a nanocomposite coating formulation designed to provide transparent high barrier coatings at thicknesses from 1 to 10 microns that include a near infrared (NIR) or infrared (IR) dye that enables rapid measurement of coating thickness and uniformity. The preferred dye imparts no observable color or appearance change, and thus can also function as an identifier for the coating.