  The fractal dimensions of color-specific paint patterns in various Jackson
Pollock paintings are calculated using a filtering process which models
perceptual response to color differences ($\Lab$ color space). The advantage of
the $\Lab$ space filtering method over traditional RGB spaces is that the
former is a perceptually-uniform (metric) space, leading to a more consistent
definition of ``perceptually different'' colors. It is determined that the RGB
filtering method underestimates the perceived fractal dimension of lighter
colored patterns but not of darker ones, if the same selection criteria is
applied to each. Implications of the findings to Fechner's 'Principle of the
Aesthetic Middle' and Berlyne's work on perception of complexity are discussed.
