[sejanus]

The thing to remember is that reciprocity failure only applies to silver based photography, as it's a function of the energy required to overcome the inertia of the silver atoms to the action of light. Digital imaging works in an entirely different way, so you're dealing with almost the opposite effect: at long exposures, random energy excitation of the individual receptors gives rise to unexpected firing of the receptor and thus the generation of unwanted bright spots in the image.