An anomaloscope was designed so that the full amounts of its red and green primaries could be adjusted to match for a protanope. After a protanope had made that adjustment, Rayleigh matches of red-green mixtures to yellow were made by a device in which the same percentage of one primary was subtracted from the mixture as was added of the other. The instrument was used to study the proposition that protanomaly is an intermediate form of protanopia, based upon the presence in the protanomalous trichromat of a diluted form of erythrolabe, which is assumed to be absent altogether in the protanope. The technique was to generate artificial protanopia in normal subjects by adaptation to very strong red light, and then to record their Rayleigh matches during subsequent regeneration. The results indicate that something more than dilution of erythrolabe is involved in protanomaly.
HOWARD D. BAKER, "Single-Variable Anomaloscope Matches During Recovery from Artificial Red Blindness," J. Opt. Soc. Am. 56, 686-689 (1966)