This Standard specifies two types of determination method for luminous transmittance and haze of transparent plastics, which are method A (hazemeter) and method B (spectrophotometer).
This Standard is applicable to the determination of luminous transmittance and haze of transparent plastics slab, sheet and film.
2 Normative References
The provisions in the following documents, through reference in this Standard, constitute the provisions of this Standard. For dated reference, subsequent amendments (excluding corrigendum) to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents applies. For undated references, the latest edition is applicable to this Standard.
GB/T 2918-1988 Plastics - Standard Atmospheres for Conditioning and Testing (idt ISO 291: 1997)
3 Terminologies and Definitions
For the purposes of this Standard, the following terminologies and definitions apply.
3.1
Haze
The ratio of the flux of scattered light whose direction deviates the incident light when transmitting the specimen to transmitted light flux, expressed in percentage (for this method, scattered light whose direction deviated above 2.5° from the direct of incident light is counted to calculate haze).
3.2
Luminous transmittance
