A reflection-type film-substrate retarder is an optical device that changes the relative phase but not the relative amplitude of light upon reflection from a film-substrate system. While there are several such device designs based on the common negative film-substrate system, very little has been done with the other two categories of systems; zero and positive. The system category is determined by the relationship between the refractive indices of the ambient (N0), film (N1), and substrate (N2). If N1<√N0N2, the system is negative; if N1=√N0N2, the system is zero; and if N1>√N0N2, the system is positive . This paper discusses the design procedure and characteristics of zero-system reflection-retarders. The polarization and ellipsometric properties of the positive system preclude the existence of a reflection-retarder. First, a brief characterization of the zero and positive systems using constant-angle-of-incidence contours (CAICs) and Constant-thickness contours (CTCs) of the ellipsometric function is presented and discussed. Then, an algorithm outlining the design procedures is presented, and the characteristics of the obtained designs are optimized, analyzed and discussed.