An Evaluation of Two Simple Methods for Calibrating Wavelength and Absorbance Scales of Modern Spectrophotometers

Two simple methods have been evaluated for calibrating wavelength and absorbance scales of modern spectrophotometers, namely, a method for wavelength scales which is based on the locations of the maxima and minima of the absorbance wave of a pair of transparent closely-spaced parallel plates, and a method for absorbance scales which is based on the absorbances of properly oriented screens of square-woven single strands of brass wire. The evaluations were carried out by means of a Beckman D.U., a Cary, and a Hardy-GE spectrophotometer. It is our hope that the simple, convenient methods will encourage more frequent calibration of spectrophotometers, especially when the wavelengths and values of absorbance extremes are of importance. (This paper deals only with methods and should not be construed as an evaluation of the performance of the spectrophotometers employed.)