Abstract: We describe a simple technique to compute the threshold at which glossy lobes in Phong or Blinn-Phong-like reflection models are negligible and thus avoid the cost of an exponentiation and a few other operations. The technique is trivial to incorporate into existing shaders. For existing shaders that already branch when the glossy term is zero, it introduces little overhead. SIMD or GPU shaders that do not already branch will incur the overhead of a branch and may experience divergence, which should be weighed against the potential advantages.