Fig. 11 shows all of the design points of the four
experiments, plotting glare reduction rating against the
calculated reference of theoretical percent glare reduction
on glass (task lighting degree of polarization of
87.5%) from Table 6. The data of glare reduction rating
for the two papers at the two test conditions follow the
same general patterns. This strongly suggests simple
linear correlations for this range of viewing angles. For
the two common papers studied, the glare reduction
rating for most actual work conditions will fall between
the plots of ambient lights off and bright, ambient lights
on, with the amplitude of the rating dependent on lamp
position (viewing angle).
Simple linear regressions were run for each of these sets
of data in Fig. 11 and are shown in Table 7. The degree of
fit for each of paper and lighting condition shows that for
these materials the specular glare on a chosen surface as
sensed by a human may be directly related to theoretical
glare calculation on a reference surface. The data in
Table 7 could also be used to generate the same type of
contour plots as in Figs. 9 and 10.
The empirical percent specular glare reduction was
measured using the luminance meter at all the same
Table 4 design points that had been used in the human
testing for each of the two papers at the two lighting
conditions. When this data was compared to the human
testing glare reduction ratings, Fig. 12 resulted, showing
a reasonably good correlation (R2=0.91) for these very
different papers and conditions. It may be concluded
that the luminance (brightness) meter and the eyes of the
human subjects respond in the same manner to changes
in glare reduction from the use of polarized lighting.
Glare reduction ratings of over 5 on papers may be
achieved at measured specular glare reductions of 20%
or greater. In this case, the correlation is non-specific to
materials over a wide range of conditions. So, in place of
using a luminance meter, one simple, inexpensive
method to see if linear polarized light is indicated to
reduce specular glare is to sit at a workstation viewing