P3D Re: pulfrich effect

[aifxtony@xxxxxxx (Tony Alderson)]

Ron Keas (digest 3094) wrote:
>I ran across a web site that described how red and cyan lenses are better
>for pulfrich effect than the one dark lens. (...) The information on that
>page claims that the one dark lens causes eye strain.<

I hardly see how the eyestrain of retinal rivalry from red/cyan glasses are
any less than the retinal rivalry of gray/clear specs. Sounds like
marketing hogwash to me.  In any case, most anaglyph filters are of
approximately the same "density", this doesn't seem conducive to the
Pulfrich illusion. Just trying it out on some movies on my hard drive, I
think conventional Pulfrich glasses are better.

and further:
>It is my opinion that the eyestrain most people experience from the
>pulfrich effect they've seen on network TV is caused by the improper use
>of motion direction. If the glasses are set up for let to right screen
>motion, to allow scenes with right to left motion is ignorant, but all of
>the productions I've seen make this mistake.<

This is an inherent problem with using Pulfrich illusion for a sustained
program...nobody can stand to shoot an entire show under the motion
constraints--it just doesn't make dramatic or visual sense. Pulfrich is
best restricted to short duration gimmicks. And IMHO, the most strain from
these shows is from the abysmal writing ;-) But in an eyestrain sense, you
might consider the problem of vertical motion in the scene--this causes
vertical misalignments while viewing.

and finally:
>What is the purpose of the light yellow colored lens on the left in the
>pulfrich glasses?<

Pulfrich's lab discovered the effect back in 1922, the invention is in the
public domain. The yellow lens is a transparent (ooh! pun!) attempt to
monopolize the market by patenting an "improvement" to the art, but as Ron
observed, it ain't no such thang.

And by the way, Ray Zone can also make Pulfrich viewers. (Don't know if he
has any in stock.) Go visit him at www.ray3dzone.com. You can email him
from there, he is also on P3D.

Tony Alderson
aifxtony@xxxxxxx
www.aifx.com



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