To the Calculation of Dominant and Complementary Wavelengths and Purity

Abstract

To date, finding the dominant and complementary wavelengths and excitation purity given in domestic standards and educational literature is rather descriptive and does not contain a clear calculation procedure. In general, for test engineers who in their professional activities rely on software measuring instruments, the current situation is not a problem. However, for developers of standards and measurement procedures it can be a serious obstacle. In this connection, the review of existing as well as development of new computer methods of calculation of the specified quantities is of interest. In this paper, we propose a new numerical method for calculating the dominant and complementary wavelengths, based on the following property. The distance between a considered chromaticity and a ray with beginning at the point of achromatic stimulus, which crosses the spectrum locus, takes a positive value on one side of the line, connecting achromatic stimulus and considered chromaticity, and a negative value on the other side. The peculiarity of the method is that both dominant and complementary wavelengths can be simultaneously determined for the considered chromaticity. In addition, the article deals in detail with the calculation of excitation purity.