A reversible thermochromic composition with light fastness feature comprises an electron-donating color former, an electron-accepting compound represented by Formula I, . Radiation so modulated and modified by the sample is detected and up to 25 harmonics may be derived from the detected signal. In various embodiments, the IP package may further include one or more selected ones of customizable attribute, UI choice elements, embedded andor diagnostic software, test vectors, supplemental generators and verification environment configuration requirement descriptions. A partially \u201cflattened\u201d collection hierarchy is created to simplify browsing the media clips. , density, porosity, mass transport resistance, thickness, or gas permeability, than a second portion of the membrane.