Re: Bears and Butterflies

[boblong@xxxxxxxxxxx (Robert Long)]

On Mon, 02 Dec 1996 18:57:05 +0000 (GMT), Wayde Allen wrote:

|The color shift is due to the interference between light reflected from
|the top of the film and the bottom of the film.  The color you see is
|related in wavelength to (twice?) the film thickness.

That could easily be true if we were talking about reflected light.
But the film was being viewed by transmitted light.  By reflected
light it just looked black while still on the aluminum substrate and,
if I remember correctly, sort of navy blue once it was removed.

|Don't know about this.  The eye doesn't see blue very well so perhaps
|the red is an optical illusion?

Presumably it is, but I wish I understood the mechanism more clearly.
I've never even had confirmation from any other subway rider that
others see the red/blue bulbs as I do.  Perhaps my own (slight)
astigmatism is a factor.  But I saw it as a kid, before I wore
glasses, and continue to see it now, with astigmatism-corrected
bifocals.

BTW, many thanks to Wayde and Hank, among other listmembers, who are
the first to give serious, substantive answers to questions I must
have been asking for some forty years.

Bob Long
(boblong@xxxxxxxxxxx)

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Topic No. 8