What is the difference between a Procedure A and Procedure B HazeMeter
A very simple explanation is that the design of a Procedure A instrument has a single detector (photopic Y C/2 or A/2) mounted on the sphere. The light source is opposite the sample sphere opening. This design can only report %Haze or %Total Transmission. It CANNOT report color such as XYZ or CIELAB. This design is the opposite of the VISTA which has the light source mounted on the sphere and the detection opposite the sample sphere opening. Procedure B instruments are transmission capable spectrophotometers that meet a few extra design criteria, such as number and size of openings in the sphere and size of detection beam relative to size of entrance and exit ports of the sphere. The VISTA fully complies with all of these dimensions.
Each VISTA is shipped with a certificate showing it's ASTM D1003 Haze performance reading 5 Haze Standards (1%, 5%, 10%, 20%, 30% Haze). If you send a VISTA serial number we can send you a copy of this certificate. Some of the early VISTA's that were shipped did not include this certificate, but all current VISTA's do ship with this certificate.