The subject invention relates to a strain-sensitive coating, a strain measurement system, and a method to determine strains on substrate materials. In a preferred embodiment of the subject invention, the system includes a luminescent strain-sensitive coating and a strain field mapping system which can be used to create a strain map of the mechanical strain on a substrate material. The luminescent strain-sensitive coating of the subject invention is preferably a polymer-based coating, and can incorporate one or more luminescent compounds. The subject coating can be applied to produce a thin film on a substrate material, such as aluminum, steel, polymer, or composite. One or more characteristics of the luminescence emanating from the coating can then vary in relation to the strain on the substrate material. In a preferred embodiment, the change in the morphology of cracks in the coating can vary one or more characteristics of the luminescence emanating from the coating such that the strain on the substrate material can be determined by measuring the luminescence emanating from the coating.