Irwin Priest was born on January 27, 1886, in the small town of Loudonville, OH. He attended Ohio State University from 1904 to 1907 where he graduated with a BA degree. He obtained a position as a laboratory assistant, moving up to assistant physicist, at the National Bureau of Standards in Washington where he remained until his premature death on July 19, 1932, [1].
59.1 Priest-Lange Reflectometer
Early on at the National Bureau of Standards (NBS), Priest became interested in the subject of color. He soon was promoted to chief of the Colorimetry Section of the Optics Division of that organization. His main effort was to find a method by which color could be accurately defined in term of physically measurable quantities. A patent for a photometric device was issued to him in 1913 [2]. He invented a dispersion colorimetric photometer for measuring light sources and an apparatus to measure dominant wavelength, purity, and brightness of color samples, described in 1924 [3]. In 1920, together with E. Lange, he developed the Priest-Lange reflectometer, in use at NBS until the 1970s (Fig. 59.1). In the 1920s, as the result of the need for a reliable color specification system, Priest supervised and advised for work at NBS and the Munsell Color Company related to improvement and enlargement of the Munsell color atlas, resulting in a new edition in 1929. The early editions had only 10 hues; the 1929 edition was enlarged to 20 hues. This effort also resulted in a number of related publications [4]. An important effort of his was the calibration of hundreds of glass filters used at the time for color measurement at NBS. In 1927, an official NBS calibration scale, known as the Priest-Gibson scale, was set up for that purpose. Its main application was the definition of the color of vegetable oil, various kinds of which were produced in the USA. In 1913, he became an Honorary Lifetime Member of the American Oil Chemists Society for his work on oil color measurement.
Fig. 59.1
Priest-Lange reflectometer at the US National Bureau of Standards
A subject of interest to Priest was color saturation or purity, resulting in articles published in the Journal of the Optical Society of America [5]. An investigation of purity at the threshold level, together with his colleague F. G. Brickwedde, was presented at an OSA conference and published in 1938, guided by D. B. Judd [6]. Priest was also involved as the chief US representative in the CIE effort leading to the 1931 CIE standard observer [7]. He was president of the Optical Society in 1928/29. Priest authored and co-authored some 70 articles on color during his lifetime.
