Abstract
Accurate linearity evaliation of spectrophotometers is quite important to ensure the reliablity of measurement. Reference materials with reflectance calibration are commonly used for the linearity evaluation. In this study, a set of reference standards with various reflectance levels was established aiming at the simple and accurate linearity checking for the spectrophotometers. The reference standards were directly calibrated against the spectral diffuse reflectance standards at NMIJ. In this calibration procedure, the linearlity of the NMIJ reference spectrophotometer was also evaluated with a silicon photodiode, good lineality of which was ascertified over a wide power range by using flux addition technique. NMIJ is scheduled to provide a new calibration service for spectral diffuse reflectance with low reflectance down to about 1.0% at the end of 2005.
