We present a function that can be used in conventional non-polarizing renderers to simulate thereflection-altering visual effects of real polarizing filters, without having to replace the existinglight and surface representations. The relevant Stokes-Mueller polarization calculations aresimplified so that neither Stokes vectors nor Mueller matrices are needed in the finishedimplementation. Our function approximates the surface’s complex refractive index with itsspecular color, and the accuracy of this approximation is demonstrated with some commonconductor materials; no approximation needs to be made for dielectric materials. As ourfunction only affects specularly reflected light, it cannot simulate all the visual effects producedby real polarizing filters, only the reflection-reducing ones. We show the visual effects of ourfilter function and measure its execution time in a real-time rendered application. The function’scorrectness is verified by comparing it with a filter implemented in a polarizing offline renderer.HLSL source code is provided for the real-time implementation.