Abstract: An ink composition including at least one photochromic pigment or dye, at least one film-forming resin, and at least one solvent in which the at least one photochromic pigment or dye and the at least one film-forming resin are dispersible or dissolvable, wherein the components of the ink composition are present in respective amounts such that the ink composition is in the form of a liquid or gel until evaporation of the at least one solvent, and wherein, upon evaporation of the at least one solvent, the at least one film-forming resin forms a film that (a) inhibits the ink composition from degrading when covered with the sunscreen product or (b) inhibits the ink composition from washing off when the sunscreen is washed off or both, the film-forming resin including shellac, polyurethane, acrylic polymer, silicone polymer or a mixture thereof.

Abstract: An ink composition including at least one photochromic pigment or dye, at least one film-forming resin, and at least one solvent in which the at least one photochromic pigment or dye and the at least one film-forming resin are dispersible or dissolvable, wherein the components of the ink composition are present in respective amounts such that the ink composition is in the form of a liquid or gel until evaporation of the at least one solvent, and wherein, upon evaporation of the at least one solvent, the at least one film-forming resin forms a film that (a) inhibits the ink composition from degrading when covered with the sunscreen product or (b) inhibits the ink composition from washing off when the sunscreen is washed off or both, the film-forming resin including shellac, polyurethane, acrylic polymer, silicone polymer or a mixture thereof.

Abstract: A device for measuring or detecting UV radiation that is usable with sunscreen, the device including: (a) a colorant layer having at least one photochromic material that is capable of changing its color when exposed to UV radiation, and (b) an over-layer atop the colorant layer having (i) a bottom surface that is in contact with a top surface of the colorant layer and (ii) an opposing top surface, the over-layer having a material that is constructed and arranged to allow at least a portion of the sunscreen, when deposited on the top surface of the over-layer, to be absorbed by the over-layer while preventing the sunscreen so deposited from penetrating through the over-layer to the colorant layer, the over-layer being transparent to allow UV radiation to pass through the over-layer to the colorant layer at least when the surface of the over-layer is not covered with the sunscreen. Also, methods for preparing and using the device.