Subtractive Theory of Color, Continued
Iridescence
Iridescence is a rainbow-like display of color such as seen in a soap bubble,
an opal, or in mother-of-pearl. Iridescence is softer and more subtle than
luster and has an illusive quality that uses diffraction to split spectral hues.
The colors of iridescent objects change in value and hue when seen from
different angles. You can create the illusion of iridescence by uniformity
suppressing slightly shaded hues uniformly in value with grey.
To create
iridescence, prepare a series of medium value tints between purity and white.
Keep tints clear, avoiding greyness or darkness. Paint as you would
normally. When finished, airbrush a delicate coat of translucent pale grey
over the entire painting until the painting appears misty. Replace touches of
pure hue. Another method of creating iridescence is to mix a series of clean
tints and add equal amounts of medium grey to each. Continue to grey each
hue creating three or four steps from a clean hue to neutral grey. Paint as
you would normally, using pure tints as highlights. This technique will
establish a general overall grey cast and lend unusual iridescence to the minor
areas occupied by the clean tint.
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