A method is designed to prepare foamed, opacifying elements each having a target light blocking value (LBVT) of at least 3, using a textile fabric substrate with a light blocking value (LBVS). The LBVT-S difference is calculated; a foamable aqueous composition is chosen; a dry coating weight for the foamable aqueous composition (when foamed) is determined to form a single dry opacifying layer that is foamed, dried, and densified to provide a dry thickness at least 20% less than the original dry thickness. The single dry opacifying layer a has light blocking value that is equal to LBVT-S, ±15%. The desired foamable aqueous composition can be chosen from a set of similar compositions to achieve the desired LBVT with the noted textile fabric substrate using suitable mathematical formula relating dry coating weight to light blocking value and a suitable data processor.