Turbidity Standards and Reference Materials is a technical paper by John Barron which provides details on the definition of turbidity, turbidity measurement, instrumentation that is used to measure turbidity and information on both formazin and formazin free standards. On-line, field and laboratory turbidity measurements require high quality turbidity standards. Reagecon provides a comprehensive range of both ratio and non ratio turbidity standards. Detailed information on these standards is available at www.reagecon.com