This paper reports by means of a series of graphs the chromaticity coordinates of certain Lovibond unit glasses and of pairs of such glasses in combination with an illuminant of color temperature 2842°K (Illuminant A). The chromaticities were computed according to the 1931 I.C.I. standard observer and coordinate system. The points graphically representing the xand y values have been labelled according to the Lovibond numbers and have been connected by lines to form a network. A similar graph is included for a few Lovibond glasses in combination with Illuminant C. The Lovibond glasses are those from the NBS set designated as “BS9940,” and the spectrophotometric data on which the colorimetric computations are based are those published by Gibson and Harris.
GERALDINE WALKER HAUPT and FLORENCE LESCH DOUGLAS, "Chromaticities of Lovibond Glasses," J. Opt. Soc. Am. 37, 698-704 (1947)