A Quantitative Analysis of Color Patterns in Polarized-Light Art

Nilus Klingel, Sachem North HS - Moon Limb, Great Neck North HS

For almost forty years artist Austine Wood-Comarow has created
fascinating images that use optical effects related to polarized light
to produce changing color patterns. She calls these works Polage, for
"polarized collage."  Polage is created by shining white light through
a sandwich consisting of a linear polarizer, layers of cellophane, and
a second linear polarizer.  Cellophane is a natural polymer with the
property birefringence that allows it to convert linearly polarized
light into elliptically polarized light, in a way that depends on
wavelength. The final linear polarizer transmits this elliptical 
light in varying degrees, creating colors.

The purpose of this project is to understand the color patterns in
Polage; the project has both theoretical and experimental components. 

In one set of experiments, the optical retardance (degree of
birefringence) of cellophane samples obtained from local florists was
determined by light transmission measurements. A typical sample had a
retardance of 145° at wavelength 633 nm. Films with a retardance of
90° or 180° at some particular wavelength are called quarter- or
half-wave plates respectively, and are very useful in optics research.
The ability to make such normally expensive components from free
cellophane is an important side-benefit.  

In the theoretical part of the project, a mathematical model of the 
Polage sandwiches was created using the Jones Calculus and Mathematica.  
Calculated transmission curves explain the color effects observed, 
predict optimal thickness of cellophane for maximum color saturation, 
and can be compared to measurements made with a spectrophotometer.

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For Long Island Science Fair, submitted 12 January 2006