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From: alain@dgp.toronto.edu (Alain Fournier)
Subject: Re: How to view Superbowl 3-D
Message-ID: <8901301528.AA29630@donnacona.dgp.toronto.edu>
Keywords: TV 3-D graphic
Organization: University of Toronto, CSRI
References: <3230@datapg.MN.ORG> <3047@pixar.UUCP> <41153818.16321@apollo.COM> <3069@pixar.UUCP> <249@ai.etl.army.mil>
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Date: Mon, 30 Jan 89 10:28:05 EST

I indeed suspect the Purkinje effect has something to do with this.
Since Purkinje made a lot of "subtle observations" (to quote R. M. Boynton,
whose book "Human Color Vision" is a must read) about human vision, he described
different effects. The Purkinje shift in particular refers to the shift in 
spectral sensitivity that occurs when the eye shifts from cones to rods (this 
is probably the effect that Craig Good had in mind when he surmised that this
transition had something to do with the "Super-Bowl" 3D demo). For those
of you in the Bay area, the Exploratorium has a demo of the effect. If memory
serves, there is a pendulum oscillating in a plane perpendicular to the
viewer, and because it's less illuminated on one side it appears to revolve
in a circle (that is there is a component of apparent motion away from the
viewer). I hope Purkinje's descendants get some money from any patent obtained.