optris CTratio Operator's Manual page 39

When emissivity is uncertain or changing, a 2-color sensor can be more accurate than a 1-color instrument
as long as the emissivity changes by the same factor in both wavelength bands. Note, however, that
accurate measurement results are dependent on the application and the type of material being measured.
To determine how to use 2-color sensors with your application when uncertain or changing emissivities are a
factor, please contact your sales representative.
optris CTratio – E2013-04-A
37