Color matching experiments use, in general, stimuli that are poor
representations of the natural world. The aim of this work was to
compare the degree of color constancy for a range of illuminant pairs
using a new matching technique that uses both real objects and
three-dimensional (3-D) real scenes. In the experiment, observers
viewed a 3-D real scene through a large beamsplitter that projects on
the right-hand side of the scene (match scene), the virtual image of a
3-D object (match object) such it appeared part of the scene. On the
left-hand side of the scene (test scene), observers viewed a
symmetrical scene containing a test object identical to the match
object. Test and match objects were both surrounded by the same
reflectances with identical spatial arrangement. The illuminant on the
test scene had always a correlated color temperature of 25,000 K. The
illuminant on the match scene could be any of seven different
illuminants with correlated color temperatures in the range 25,000
K–4000 K. In each trial, the observers, who were instructed to
perform surface color matches, adjusted the illuminant on the match
object. Constancy indices were very high (0.81–0.93), varied with
the color of the match object, and increased with the extent of the
illuminant change. Observer's mismatches, however, were
independent of the extent of the illuminant change.
Separate and Simultaneous Adjustment of Light Qualities in a Real Scene