Measured values versus artistic input : Shading and material creation for film

Abstract: How important is a perfect index of refraction value for the look of a material? Does everything have to be physically accurate to be percieved as a photorealistic material? There are some aspects of a lot of materials that is already physically measured, like its reflectance values. Are all these measurements enough to create a material that can be percieved as photorealistic, or are there other more diffuse things that needs and artistic input? This paper will take silver as an example. Silver often has two distinct types of oxidation: one semi-transparent yellow-ish coating and one more black opaque tarnish. Is this something that can be dialed in from derived data? What properties of the metal will change when the oxidation occurs and how will it affect it look of it from a shading perspective? Silver utilitys will be thoroughly examined to make out what important visual cues there are, and what they are made of. This information will then be used to create a silver material that could be percieved as real. A reference silver cup will be used as a comparison next to the rendered material.