The original AO HRR color vision test has been considered by many as
one of the best plate tests. It is still accepted by many governmental
agencies for color vision certification. In their 1954 publication, Hardy,
Rand, and Rittler stated that specially compounded inks were used for
printing to avoid color changes with time. Fifty years later, it is both
important and interesting to determine whether the wear and tear cause
significant color changes. The chance finding of a never-used second
edition offers an opportunity to evaluate the color changes. A
GretagMacbeth Spectrolino spectrophotometer was used to measure the
chromaticities of the never-used book, and an extensively used book. Four
plates (#4, 7, 13, 16), selected randomly from the four red-green
sections, were analyzed. The colored dots from each of the eight plates
were plotted on a CIE chromaticity diagram. Isocolor lines were drawn to
evaluate chromatic alignment. Chromaticities for plates #4 and 7 are
significantly different between the two books. With regard to alignment
with isocolor lines, the extensively used book is better than the
never-used book for plate #4. There is significant misalignment on
plate #7 for both books. Chromaticities for plates #13 and 16 are
essentially identical between books, all with good alignment with isocolor
lines. The overall comparison shows that the chromatic alignment
characteristics of the extensively used book are not worse than the
never-used book. Since colors in these plates have to be aligned with both
the protan and deutan axes, any significant color changes would have
disturbed this delicate requirement. The findings of many plates with good
alignment, and the lack of differences on plates #13 and 16 between
books, suggest that there are no significant color changes over time.
Differences between books on plates #4 and 7 were likely the result of
the original printing process.