Effective model of black hole electromagnetic interactions

We develop simple effective model of black hole event horizon electromagnetic interactions. The event horizon is represented as a membrane located at constant value of lapse possessing arbitrary complex conductivity. We derive important relations governing electromagnetic interactions of membrane and consider implications of changed boundary conditions on horizon on formation oof jets and imaging of black holes. Modified version of Znajek condition is derived. Power output of jet is calculated; it appears to change between those of black hole jet and pulsar one. Images of membrane surrounded by several types of accretion disks are produced; nonzero reflection coefficient of membrane leads to appearance of new features observable inside the black hole shadow.