Precision of Color Measurement with the GE Spectrophotometer. II: Photometric Accuracy.
The supplementary light method of Reule was applied to calibrate a simple phototube photometer to an absolute accuracy of +/-0.006% (95% confidence limits). The photometer was then used to determine the photometric accuracy of a General Electric recording spectrophotometer. The photometric scale of this instrument was shown to be accurate to within 0.1% over its entire range.
Rhodes
E C
EC
Billmeyer
F W
FW