Most infrared (IR) optical systems use blackened surfaces to reduce stray light. This blackening may be in the form of paint, chemical blacks, deposited metal blacks, or anodization either dyed or undyed. One method of determining the optical absorption of these surfaces is by measuring their spectral emittance. We have made such measurements on a number of samples in the range from 3 to 22 micrometers and on a few samples as far as 125 micrometers. Since the absorption properties may be temperature dependent, we have made the measurements at or near the ex-pected operating temperatures of the samples. Data are presented on a number of samples at temperatures from 4.2 K to 373 K.