Haze and Transmittance - ASTM D1003
The percent of incident light that is able to pass through a material. The higher the transmittance value, the more transparent a material is.
The percent of transmitted light that is scattered more than 2.5° from the direction of the incident beam. Materials with haze values greater than 30% are considered diffusing.
Testing is performed in either a Hazemeter (Procedure A) or a Spectrophotometer (Procedure B). In both cases, light passes through the test specimen on its way to a photo detector. When Hazemeter and Spectrophotometer values do not agree, the Hazemeter values take precedence.