High Quality Content by WIKIPEDIA articles! The Phong reflection model (also called Phong illumination or Phong lighting) is an empirical model of the local illumination of points on a surface. In 3D computer graphics, it is sometimes ambiguously referred to as Phong shading, in particular if the model is used in combination with the interpolation method of the same name and in the context of pixel shaders or other places where a lighting calculation can be referred to as “shading”.