Haze and Luminous Transmittance of transparent plastics. In this test, haze of a specimen is defined as the percentage of transmitted light which, in passing through the specimen, deviates more than 2.5° from the incident beam by forward scattering. Luminous transmittance is defined as the ratio of transmitted to incident light. These qualities are considered in most applications for transparent plastics. They form a basis for directly comparing the transparency of various grades and types of plastics. A hazemeter and/or a recording spectrophotometer are used in the test. ASTM D-1003.