Correction methods for integrating‐sphere measurement of hemispherical reflectance

Abstract

Abstract Integrating‐sphere reflectometers in spectrophotometers and colorimeters suffer from several types of systematic error. The properties of an ideal sphere and the main shortcomings of practical spheres are discussed. Some common errors that occur in measurements of hemispherical reflectance have been investigated using a Cary 14 spectrophotometer fitted with two different integrating spheres: a Cary type 1411 attachment and another made at NPL using a G. E.‐Hardy spectrophotometer sphere. The methods described here can be applied to almost any sphere instrument, and possible solutions to problems with other sphere designs are also suggested. It is shown that significant corrections are necessary in many cases.